The game defines small, medium, large as 10, 15, 20 per player (altho that is a really old definition) but for most discussions here Im willing to accept those. With a 1 or 2 dominion pretender you can operate for awhile outside of your dominion for purchasing new units for your armies.
And yes, in such games the capital population can get dropped fast. Ive had some games wipe me out quick but not "high probability". I usually manage to get outside of the capital province.
Both of the thematic pretenders appear to be for pushing a non-gold strategy. But yes, Pans are the biggest problem with that. Sometimes you have to stop an army at a high pop province to partol/high-tax a turn or two. Pushing a stealth army far to start a new foothold far from home helps also.
Its definitly fun for diversity play Granted Im abit more worn out on regular play than most.
I didnt say it was preferable
just not unsurvivable.