The three things i don't like currently are:
- in most situations mines are underwhelming, and require no thought and almost interaction from the user, but still are often useless (solved by detonatable mines)
- a shield is the only way of defence (solved by detonatable mines)
- recovering from a hit can take forever, making the weapons too effective, a single rocket can give a lead of 1/3 of a lap in certain situations (solved by higher acceleration of cars)
If there were detonatable mines as a second way of defence, players wouldn't be entirely relying on shields, mindless mine spam would be reduced -> easier catch up for the players behind and players would be more involved with mines.
It would allow for much more combat without breaking the flow, because getting shot at by 2 missiles in a row would not necessarily mean that the player will take a hit.
Regarding having a max amount mines while not being able to destroy / get rid of them them:
It is not fun if you, can get a random Power -> UP <- which you can't get rid of without doing harm to yourself. It is ok however if you can get something that simply doesn't help you, imo.
Just imagine a weapon in an FPS that can one shot everything, but has a 5% chance to hit the player. Worst design ever.