My PDC was like that - very little resistance, and the slightest knock to the switch & it went into reverse (usually at the most inappropriate time!).
Then, one day, I got it out & suddenly there was no resistance whatsoever. If you tipped the drill to the right, it literally 'fell' into reverse; tip it to the left & it fell back into forward. Would have made quite a nice 'hands free' feature, if it wasn't totally impractical & unusable!
I sent it back to Festool for repair, and it came back with more resistance than it ever had even when it was brand new.
I bought mine when they first came out in Festool guise. Newer ones that I've handled are stiffer, like when mine came back for repair. This leads me to think that maybe Festool have fixed the issue, and maybe the newer ones are OK?