I totally agree with you on this. I don't think it is fair to incentivize players to stand still in a meta where doing so almost certainly means insta-death. My first toon was an archer, but it was really difficult to optimize the build because of the passive you mentioned. I leveled up another character and went the Warden route, but honestly the gameplay hasn't felt half as compelling to me as Archer. I still die if anyone jumps on me, except now I just don't do as much damage otherwise.
I like your idea about the stacking auto-enhancement passive, although I think there is room for the window to be lowered to around ~10s. 15s seems excessive in both large and small engagements. I think another way to balance a change such as this would be to stipulate that Archers cannot enter stealth or something along those lines. Anyways, I agree and hope that ACE would consider changing the passive as it renders the tree essentially off-limits to most players.