They did some neat game mechanic tweaks, especially of the previously useless units: mechanics and thieves being able to revive and capture vehicles. Keeps the spirit of the old game but makes it more fun.
Not with tractors, but allied factions can do that with mechanics by capturing destroyed soviet tank husks. This is a worthwhile tactic because the soviets have bigger, more expensive tanks than allies.
You,didn't think about it as a kid because the original Red Alert didn't include a nuke truck. Although one of the expansions (Aftermath?) did, it wasn't exclusive to Ukraine.
The nuke truck was made the Ukrainian unique unit only in OpenRA.
Original RA had a tendency to devolve into tank spamming. That takes skill. But it's closer to tactical than strategic. Does OpenRA deal with this in any way?