Yes. This won't solve (or break) the gap between newer and older players, but it'll help lessen the gap. The game's overall city inflation needs to be matched by reducing obstacles for newer players. Otherwise, they'll realistically never catch up.
Players don't learn the game by being artificially stuck at c10. By c15, they'll likely be unable to afford c16 within the next ten days. I don't think this will substantially impact mass building, given that credits already offer a way to do that and wars generally aren't decided in the c10-15 tier.
Though removing timers entirely makes sense since the actual cost of each city is the limiting factor, not the timer, at higher cities, completely removing the timer diminishes the value of credits. This would reduce the monetization of the game, which would probably negatively affect the game in the long run.
Starting nations at c10 seems drastic and would probably negatively affect raiding in ways we can't know for sure. New players already get to c10 quickly.