Yeah, the old aerodynamics was pretty horrible. Add a nosecone to your blunt-tipped rocket and it increases the drag? What kind of logic is that? It needed to be fixed.
There's a couple balance issues I'd like to see fixed, mind you. For example, it's possible to make small solar ion-powered aircraft in Kerbal. But only small ones, because all of the ion engines available are tiny, and all of the fixed solar panels are tiny, so while technically it's possible to make bigger craft, the necessary part spam makes the game unplayable. Fuel for ion engines is also absurdly and unrealistically expensive for no obvious reason. Yet solar panels and RTGs produce orders of magnitude more power than they should for a given size, if ion engine power to thrust ratios for a given ISP are used as the baseline.
Drop xenon costs, tweak power production / consumption for existing hardware, and add in nuclear reactor power sources (after all, they have nuclear rockets, we know kerbals understand nuclear physics), and and you could balance that out pretty well in terms of both gameplay and at least slightly more approaching realism.
(Note that one may be tempted to say that the ion thrusters are far too high power, but at least that's plausible if we assume that they're MPD thrusters with some type of advanced cooling system - you can get crazy power to weight ratios (by ion standards) out of MPD thrusters if you could somehow supply them many megawatts of power and dissipate all the waste heat - they manage it in pulsed mode, at least. But Kerbal's solar panel area-to-thrust ratios at the given ISP are not even close to being compliant with the laws of physics)