What makes a true C&C game is a game that holds itself true to what C&C means. Building structures from a general Construction Yard and resources to be collected into a "refinery".
RA3's Ore fields felt a bit meh in my eyes personally. At best what C&C 3 has can be seen as the most desired route, although some prefer the route that RA2/TibSun have, however modernization is a thing and C&C 3 definetly is a great game on it's own and stayed true to C&C's core.
RA3 overdid it with slapping abilities on every single unit in the game and kinda overdid it with the theme. Yes the Red Alert series were the colorful ones of the two universes (not counting the Generals universe here cause it was only one game and an expansion and it does feel out of touch with C&C, maybe due to there only being one game in the series), however RA3 overdid that by looking very cartoonish. Building deaths looked just as if you threw a rock at a badly built LEGO home.
The part with the abilities just felt like they tried to compete with StarCraft, which was a pretty bad attempt imo. It doesn't fit C&C and probably never will.