The reason I main Pac-Man is directly influenced by a long and gradual period of becoming more familiar with the character.
I'm what some may consider a hardcore speculator. I spent years framing up scenarios and formulas in order to deduce who and what would get into Smash 4. Unfortunately, Sakurai's curveball approach this time left me with much time wasted, but it was fun. Whenever I noticed a character who I thought would have a shot of getting into the game, I'd bounce ideas off of my friends and others to see what their opinions were, and hopefully develop some ideas further. Even though I'm a fan of older games (the only "current gen" game I plan to play much at all these next few years is Smash), I had never even considered Pac-Man as a candidate for playability in Smash until Bandai Namco was confirmed to be making the game. I don't think the ideas of Pac-Man and Smash ever crossed my mind at the same time before then, which is incredibly odd to look back on, given that Smash is such a huge part of my life, and that I was always aware of Pac-Man's importance in the video game hobby that I've always so enjoyed; I even owned a Pac-Man t-shirt at some point. I really can't explain it, but Pac-Man was just a really obvious pick that somehow always eluded me even as I was hard at work crafting speculation theories.
Even after Namco was announced to have gotten on board for Smash 4, I still didn't give Pac-Man much thought. I had finally been given the chance to consider the idea, but I mostly ignored the thought because I figured it was better to just ignore the possible ramifications of Namco's involvement; to explore their vast library of usable properties would simply lead to disappointment should they have not received a character in the end anyway; besides, I'm not much of a fan of Namco IPs past the arcade era. Indeed, Pac-Man was just a small blip on the radar for quite a while, but he was always on the back of my mind, and as time passed, he began to inch gradually closer to the forefront. At first, when considering third-party characters, I thought of Pac-Man as something that would be nice to have; I certainly wouldn't be opposed to him, but I didn't label him as a necessity as I did with Sonic and Mega Man. Whenever I brought up Pac-Man as a possibility with my friends, the reception would usually be lukewarm or mild, and they would usually share my sentiments: It would be cool, but nothing to get excited over.
I don't know how, but it eventually dawned on me that such a reaction was unorthodox. Pac-Man was a legend: one of the biggest mascots in video game history. I was never too fond of the character, my only substantial experiences with the series being with the arcade original and long-weathered memories of playing Pac-Man World on the PlayStation as a youngster, but I of course knew how legendary he was in the gaming industry. I began searching out other Smashers' thoughts on Pac-Man on the internet, and this type of apathy was quite common, in addition to a massive amount of heated truculence that I did not think would have existed. As I came to realize how odd it was that so few people wanted such an icon in Smash, my passing interest evolved over time into a more positive intrigue in his inclusion. By autumn or winter of 2012, I was a passionate supporter in all but self-recognition. I desired Pac-Man. I truly wanted him in Smash. My change of heart can be partially attributed to my personal interest in all things Christmas and animation leading me to rewatch the Christmas special of Hanna-Barbera's Pac-Man cartoon, which I ended up writing a review of. This special was another foggy memory of mine, and was something of a guilty pleasure that I enjoyed watching with my father when I was much younger. It's no coincidence that the viewing of this Christmas special coincided with the time when I became a supporter; my renewed interest in Pac-Man helped lead me to review the special, and that in turn further fanned the flames of support. Surely, I must have reflected at the time, if Pac-Man was so culturally significant as to have a Christmas special produced for him, then there must be some value to be had in dusting off the character for use in a mascot fighter of Smash's scale. I began researching Pac-Man much more thereafter, and I began to fall in love with the IP and its history. In an industry as vicious as with video games, any character that could have such a lasting and felt impact after over 30 years would earn my respect quite easily. As a history buff, I'm inclined to appreciate anything that can leave such a mark on society that its influence is still seen and recognized years later.
In the span of about a year, I went from barely acknowledging Pac-Man's existence in regard to Smash, to him becoming one of my favorite video game characters of all time (shout-outs to the Pac-Man fan community here on Smashboards for playing a part in this development). He quickly shot up through the list of characters I most wanted to see in Smash, surpassing just about everyone, even my next most wanted: King K. Rool. Pac-Man went from something I would have liked to see, to something I needed to see to be content with the game. Since I'm already satisfied, gameplay-wise, with other games in the series, I can say right now that there's a chance I wouldn't have even bought the game without him (the only other newcomers I like are Villager, Little Mac, Duck Hunt, and Mega Man, and I only wanted two of those). To have Mario, Sonic, and Mega Man all together in the same game, and not go that one small but profound step in adding Pac-Man would have been one of the most disappointing moments in gaming history to me, no doubt. With Pac-Man's eventual inclusion, Smash Bros went in one step from being a celebration of Nintendo's history to a celebration of gaming history in general, a title that cannot be deserved by any work excluding Pac-Man. And despite what many people have said, Pac-Man is also significant in Nintendo's history specifically, something I learned through months of dedicated research and which I explained in the OP to the character's support thread. I expected him to fit right in with Nintendo's roster, and he did. The iconography used in his presentation in Smash, such as the 8-bit fruit and ghosts, are so ingrained into video game culture that they don't look out of place next to other iconic retro gaming material, like Mario, Mega Man, Link, etc. As a video game player, I was already used to seeing Pac-Man ghosts juxtaposed with Mario coins and E-tanks anyway, so when he was finally shown off at E3, it felt like the last element of that gaming milieu had finally joined the collage that was already near completion.
By the time of Pac-Man's announcement, he was already established firmly as one of my favorite video game characters and the newcomer I most wanted to see, so he was a natural main for me. When I finally got the game, I loved everything about him. I have an affinity for characters that seem to enjoy the competition they're in (one of the reasons I love using Toro in PSASBR, as an example), and Pac-Man is just a constant transmitter of happiness, with his wide grin, sunny yellow coloration, and nonchalant use of everything memorable in his historical toolshed for his moveset. While I normally enjoy playstyles closer to the fast and powerful rushdown variety, such as Melee Falcon, I also like characters with strong defensive options and good stage control, which Pac-Man has in spades. I must admit that I wish that Pac-Man had more of a speedy, movement-based playstyle, but for what it's worth, he still ended up with one of the most interesting playstyles out of all of the newcomers, in my opinion. Pac-Man's moveset is simple, yet wide-ranging and variable; it encapsulates the type of playstyle I like more than any other. That's why I main Pac-Man. He has so much personality, and such a commanding presence in the roster, that if he ever gets cut from future titles, I'll truly feel like we'd be losing a lot more than just my main. I think a lot of Snake mains felt this way in regard to Smash 4.