The two big ballers in standard right now are Valakut and Splinter Twin, and neither of those care about your sorcery-speed creature stoppage, so I'd cut Omens and DoJ and move 3 Timely Reinforcements to the main to cover all those creature/aggro matchups.
Ponder and Preordain are both legal, and they're both good enough for legacy, and they're both common. 4 of each.
You have too much high-CC stuff. I count 12 cards CC5 or higher. Most decks are much faster than that. You have 4 Ponder and 4 Preordain, so I'd try to cut that down to about 8. You choose. Personally, I think Venser and Sun Titan don't belong, as you don't have enough targets. Tec Edge is basically the best thing you can be doing, and you'll have enough of them if you need to find them. You definitely want a singleton Karn if you can get your hands on it. Again, you're cantrippin', so you'll find him as soon as you get that high. 8 library search also means you can cut a single land if you want.
I'd add more counterspells. Keep them spread out, since you can find the one you need when you need it.
The last couple slots can go to singleton blow-out cards like Revoke Existence and Surgical Extraction (kills Twin and Bloodghast Shenanigans). I wouldn't add low-CC creatures, since Dismember is everywhere and you have no other targets for it.
Edit: Tempered Steel is a real deck. Side Revoke Existences.
Honestly? I disagree with most everything you just said.
Especially using Ponder AND Preordain. The only deck that needs that is Pyromancer Ascension, and last I checked that wasn't this deck. Preordain is strictly better than Ponder, so it sticks. Ponder just isn't very good.
I have a lot of fatties because my deck revolves around Venser doing sick **** with them. Venser plus Frost Titan wins me most of my games because they stop the opponent from doing anything with their field.
Sun Titan grabs tectonic edge, dead Colonnades, Jace Belerens, Oblivion Rings, Wall of Omens, Spreading Seas, AND Kor Firewalker. Sun Titan and Venser means I'm allowed to be risky with my deck. Revoke Existence is garbage when we have Divine Offering, and Divine Offering has no reason to be main boarded unless you're very scared of spellskites, which Dismember bodies.
My meta also plays a ton of aggro of control, very few combo, and DoJ is a baller against every form of aggro except Glint Hawk Idol, Gideon, and man lands. I barely want to take out a fourth DoJ, but I am because I kind of have to to make room for O-Ring. Omens are arguably one of the best easy Venser targets, stops aggro, keeps me from dying to Phyrexian Obliterator, is grabbed by Sun Titan, and can't be bolted.
The deck has a lot of synergy, and TBH most of your suggestions were just bad for what I'm trying. I have a crazy good matchup against Valakut; it's a joke to my deck. Splintertwin on the other hand is another beast, but the suggestions you made doesn't stop the twin besides the way already too late Surgical Extraction.
Sorry for bashing everything you said (and how bad my spelling is today), but I think that you're completely wrong.
And I used to mainboard six counterspells, but they just aren't important right now where I play. Spot removal and interactions is more important. And then my 5 hard counters still get the job done regardless.