Sounds like a good idea.
Reason why you want this is probably cuz of the guild war.
I dont think changing the price will do a huge difference but it will probably help a little, but an longer exhaustion on the rune sounds good, especially in the guildwar.
Also one other option(for the gw) would maybe be to change the map, maybe more entrances to the Nexsus.
If they change this, the tactic will most likely change. It's risky to block at the Nexsus so players will probably go back to blocking the bridges, will be more teamwork and hopely more fun.