Thought HH is still alpha with lots of issues and things to add - game is definitely mature enough to stop and think about service quality. Constant lag issues is not correct case. In such rare conditions (mostly right after downtime when heartling counter is low) when game runs smoothly - HH is different. Much more attractive. You should play against game-goals, not contest massive lags (not mention that some parts of game is not-enjoyable with lags at all). HH is serious time-sinker - those is normal - it designed in such way - but those time-sink should be rewarding and lags are just punishment with no reward.
So solution: lets add some way to feed developers with real-world money. So they can invest in better equipment (and in future - have more will to spend time on HH improvements). I mean - HH has great core idea and hardcore sandbox is place where indi-developers can have huge success. But games (and MMO especially) is not thing you can do "in spare time" good enough, I tell those as professional game-developer with AAA-titles-background so just trust me =). If we want perfect HH - we as community should pay. And as we expected to pay - we should have meaningful way to pay.
Current PayPal donate is not nearly enough (PayPal is not available for many-many peoples. And they have dark roots so many ppl avoid PayPal at any cost). May be current week/current month meter should be added so we can see is enough money collected. As large chunk of population is from Russia - also national payment systems should be added (money.yandex.ru is example of good solution. They have simple donation func afair). Those I hope is considered nice by everyone.
Now lets move to more debatable thing.
Ingame advantages by real-money. As sandbox is so fragile and easy to break selling resources or advanced thing is not acceptable in any way. Game is about player-created-world and have to be left so. Those is what makes HH attractive and harming "closed sandbox world" mechanic should be avoided at any cost.
So what is left? Special status will work. Like premium blessing. I can see it as "pay some bucks and next month you will receive special buff". Simplest effect is +25% LP gain bonus (over all other calculations, so you will receive 125% LP ratio with default sliders and with full change/peace - 450% instead of 360%). Nice to have for active players but still acceptable for those who does not want/not able to pay. I see no pitfalls except of loosing special aura of non-payable-underground-hacking =)