First let me start off by saying that Travian is NOT pay to win.....no one person can..."pay to win"....its a team game...sure having gold helps you with your acct....gets you top quality gear...perhaps even 1000's of animals for protection, but none of that will help you win the game....you WILL need the help of your kingdom. Secondly...I have played this game with gold and without....and as long as your within kingdom borders helping your kingdom....playing without gold works just fine. In my opinion the most important thing about this game is being active...having sitters and/or duals to keep your acct raiding/building.
Now if the problem is mid server burnout....than that is a Travian problem...not a gold problem. Travian should introduce more ways to keep people involved in the game like Kingdom quests...sort of like personal quests you get from the start of the game....giving players and your kingdom goals to add bonuses to certain aspects of the kingdom. Travian should also institute some way to help players recover their troops quicker if lost.....I see alot of players delete after losing their hammer.
In conclusion, I think if Travian shifted to a subscription based game....it would drive ALOT of people away from the game. I for one would no longer play Travian if this format was introduced....I like playing with gold...but i dont abuse gold...dont need to.