Seems a bit complicated and long winded or; more work than what it is worth.
I get why devs limited the usage of nade traps, but honestly no one uses them.
Instead of having a whole new class, I would be in favour of increasing the limit to 4 nade traps per player (whilst still leaving the team-wide limit in place) so that they players that actually do plant them can actually put up a good defense with them.
A comment from a dev would be nice.