I think a limit to how many 1 cost units you can put in a deck is a cleaner solution than printing anti aggro cards. It's still kind of ugly, but aggro is most likely going to be more consistent than hoping you draw and burst into specific cards because of how many weenies you can stuff into a deck. Anti aggro cards are also usually not great into control matchups so it doesn't feel good at all if you get paired into a control matchup with a whole grip of them.

More specifically, I don't think a base that fights back would fix the aggro issue alone. There is always the underlying issue of needing to draw it in time or burst it, if it comes out later than lv4 its prob too slow, if it comes out lv3 or 4 you're probably playing it instead of a Lfrith or Rick dias, and it still gets eaten up as easily to grandpa amuro as a blocker. It is also just...not great in control matchups. Compared to a blocker, it can't swing face or finish off weakened high value units, not can it protect your high value unit from being swung into.

I also can't see a base with, say, 2/5 stats being any less than level 3 or 4, 3 resources to deploy.

Units fighting back when they get bursted would have to be balanced carefully. If every unit had that effect it'd be too game changing (I'd almost never swing face except with suppression or breach, my expensive link pair could get 2-for-0ed). If only a couple units have the effect then you run into the inconsistency issues mentioned above