I've played it Beatz, otherwise how would i have experienced all this melee only malarchy on your map
Just because it's a gimmick map, though. Doesn't mean you shouldn't attempt to make it play better, if it can.
It's just that right now, the players arn't exactly engaged because they don't
have to cross paths with the enemy (and on the first stage, if they do, it usually results in spawn camping. So that needs to be resolved by widening the map in general). It's generally just scouts and spy's doing a few flanking manouvers, but not really managing anything against the enemy cart because they are too weak as classes, and the cart is also healing everyone on it and the close concentration of players makes it impossible to infultrate (IE scouts and spy's are like predators, stalking the heard and taking out stragglers). Which makes it especially difficult to dislodge heavies and soldier's when they all group together on it.
Snipers can be effective at clearing the cart because generally the players are stuck out in the open when pushing it. Unfortunately that also means you're gonna get less people pushing your own cart. Usually this wouldn't be a significant problem for PL (although it does cause stalemates in goldrush), but for some reason it has more of a negative impact on your map than others.
As i said, just because it's a gimmick map by design doesn't mean you have to submit it to the problems that plague other gimmick maps such as spawn camping, class imbalances and generally gameplay that rewards griefing tactics. The very fact that you've chosen a PLR mode implies the intention for team interactions beyond what idle, orange and mariokart maps currently offer; which is a never ending meat grind.