They could simply add all countries with more than 10 million internet users.
But that means countries would farm bonus from those small countries, and then most would be pto'd (now even more with the dictatorship module) and then the game would be ruined even more.
They need first to:
1) Address the strenght issue, a suggestion is to remove divisions and only give 5 BH for each side every round, make it 6 rounds of around 1500 points for each round, for epic rounds they could simply make that you require double points (epics last more, more people fight, more people buying stupid crappy packs to win the battle, more profit for Mr Plato).
2) Address the political inactivity, right now being a "politician" is only a burden, either you become a villian and sack your country or you will simply never get anything for it... Plato could implement salaries for politics that congress vote for them (so more people become actually interested in using those charges even if its just by greediness), also ministeries should have power related to their ranks, example: a Mofa should be able to propose an MPP (and congress vote) and a Mod should be able to propose an NE (but again congress vote), in dictatorship you could actually set if your dictatorship is going to be parlamentary (like giving power to a congress) and turn into some kind of monarchy or simply hold all the power over you (this would totally improve the politics). Also countries dont need 40 congressman, it should be reduced to 20 normal congress + 1 per region conquered, its hard enough to find enough people to run a whole goverment... think about a congress...
3) Press module still needs improvement... how can we be in 2015 and have no html press? This is simply quite stupid... also more people would like to involve in press making if you actually could make people pay a "quota" to see your press... it should be optional though, also endorses were nice... but its simply non-realistic.
4) Goverments need more benefits. Countries hardly play anything on this game, what can a country do? Try go get the 15/15 bonuses... then what? Poland was a major powerhouse very coordinated with a very strong overall population, now they achieved all the bonus... why would they go to war? Why would they use their taxes? The goverment of a country has no sense at all... If (in other hand) Goverments could have companies (run by citizens but state owned) you could actually introduce communism ingame... also if Goverments were able to have a National Forces with some kind of wage if you participate in military objectives... it would simply make a lot of sense. Goverments play no part on anything currently and its just a huge burden because everything is outgame. Have you tried calculating how much money you get from each tax simply to know what should be raised and what not to try encourage people set one kind or another of company? Its simply stupid.
5) Economical module: Everybody thinks that economical module can be fixed if you remove WAM... house companies prooves otherwise. How can the houses be so cheap while so expensive to do? Nobody knows... a House should not be profitable, yet they are, and people keep building them at "low" prices. Its simply bullshit... either because salaries are being payed under the table (so no taxes are payed to goverment) or either by slavery/use of multiaccounts. This should be addressed ASAP. If a country managed to run a "house" monopoly (like producing houses cheapper than anybody else could) i could simply understand it... but definetly this isnt the case.
Also ingame currencies for each country are a must... they are simply a must, having a different market on each country would simply make everybody think "its worth that i stay here? couldnt i make more benefit if i was with my companies in a smaller country because there is demand but no one is producing there?" Migrations are ok, but ingame there are no more migrations, people dont even care any longer about bonus, they keep producing with no rentability. Also companies shouldnt move with you.
And well... as i was writting this i was realizing nothing of this will be done... so i wont bother following... there are thousand possible ideas... but they simply take non... if they had other plans i could actually understand but there are no other plans, they are simply killing the cow while milking it...
I can only hope a new "erepublik" borns with a serious company and it actually grows.