Six vehicle skills that you would need to revisit at most every level, instead of two? No thanks.
Similarly, weapon proficiency feats are a one-shot acquisition. You don't need to keep revisiting them. If you want to be better at them, raise the appropriate stat, take the Weapon Focus feat for that weapon, or level up in a class that has a good BAB progression.
Well, you may as well argue that all skills are unecessary and should be replaced with feats
. You're going to be "revisiting" all skills anyway.
My experience with d20 is entirely through D&D3.5e. My character - a fighter - was increasing things like Hide and Listen and Spot every level (and he got barely any skill points at that, and most of those are crossclass skills so he needed to pay double for them). I wouldn't have complained if he had to do that with a Bastard Sword skill too - as it is, he had to burn up a total of three feats over his 13 levels on Exotic Weapon Proficiency, Weapon Focus, and Weapon Specialisation to be reasonably good at it. But to do that, characters would need to get a heck of a lot more skill points and ditch the BAB. Now, as it is, the BAB increased with each level, but the only way to actually get markedly better in the general use of a Bastard Sword over any other weapon type was to take the feats - there was no skill-like way to increase the BAB.
In a BAB-less d20 system, I'd envisage that the weapon skills would directly replace the BAB. Maybe you could have class-based tweaks (like, martial types would automatically have level 1 in every weapon and armour skill, so they at least knew how to use everything even if they didn't know it too well). And there would be a lot more skill points to throw around to start with and per level too. Feats would just be reserved for manoeuvres like Far Shot, Cleave, Critical Strikes, Quickdraw, Speedy Armour Removal, etc and not for just knowing how to use the weapons and armour.
As for vehicles in T20, that would be similar. Ditch the feats, and just use skills. Use feats for things like "Stunt Driving" or "High-G Manoeuvering", and let the skill level reflect how well the character knows how to fly or drive the vehicle. Heck, while we're at it, make it more specialised and realistic anyway - someone who only knows how to fly a propellor-driven crop-duster does not necessarily have any skill in flying a helicopter or a hot air balloon or a state-of-the-art jet fighter or stealth bomber well.
As it is, we've GOT Driving and Pilot skills in the game. We already have the ability to distinguish between a good pilot and a bad one - so what the heck is the feat doing there anyway? It's completely redundant, and means that feat slots are taken unecessarily by things that are already covered by skills.
