Vests dont play a role. The size of the RC resource pools was set by developers based on their assessment of hardware resources and likely hardware improvement trends over time. To change those assumptions requires a fork, but forking to change the assumptions doesn't, by itself, change the reality of hardware resources.
Other than that, your comment is correct. More actions will increase the RC cost associated with each action to rebalance back something in line with hardware resources.
Thanks for the response - I thought for some reason the "size of the pool" was relative to total vests, thanks for the correction.