There's certain things about the rules for vehicles which I hate and love.
I hate that strength 5 now is a main weapon. I remember when it wasn't.
I hate that you can now assault it from any side and the hits go on the rear. It was logical when the hits came on the facing you'd be in contact with.
I love that the damage charts have been improved to make them more survivable in battle. And hope it'll continue to be so in the next edition.
I'm not too fond of the vehicle squadron concept. To think my tanks in a squad must all fire at the same target. And since my tanks are always a mix to make them more versatile it often means some weapons may be ineffective depending on the target. The upside is they're a little safer now in squadrons.
And it never made much sense to me that a vehicle must turn all of its guns on one target. You have crewmen for each gun. And sponsons. Logically you'd think they could fire at will when targets are presented. The Baneblade and other superheavy tanks can and so they perform more like you'd expect a vehicle too.
I would like to see better upgrades for vehicles. I recall an Imperial Guard Armored company that had doctrines for the tanks. And some essentially worked like vehicle upgrades. I'd not mind seeing these brought back to life in the form of additional upgrade options. Like anti-mag coating on your armor making it harder for mines and bombs.