Id say, if your willing to play comeptitively, you have to change your frame of mind. You have to realize that some charecters just have huge advantages over others when it comes to certian At's (WD) and get-backs. Mainly if you think you can competivley play and win by being a low teir charecter and playing the balences game like you would the comp. you might want to rethink your strategy or frame of mind to playing a high tier charecter and using the moves that work best with their at's. Im all about trying to win these tourneys with other charecters outside of the predictable teir list, but when you get down to it, the diversity of winnning charecters dwindles the tougher the competition.
But as far as getting your charecter (weather low tier or w/e) you can incorperate the WD tactics into them and start playing more ppl competitivley. Its tougher for some charecters than others though, be prepared to lose to some really adventageous combos.
And for playing the comp, they serve really well for learning what counters what on a basic level. and IMO (this is my opinion evreyone) Basics is a HUGE factor. Im talkin like how far exactly your tilts hit, power sheilding, range precsion on all of your attacks and sweet spots/hit boxes.
so i guess in short (now that im done hearing myself talk haha.) evreything you do goes into the pot of improvement, play more crazy WDshrs and learn from them as well. But if you want to win, be prepared to change strategy and sadly enough, your charecter (eventually that is). Good luck keep playin dude.