Well its sort of a must for almost all visas I guess. We haven't helped our reputation by exploiting the immigration laws of most countries either. A strong bank statement is needed to show ties to your country and provide proof of financial stability, that is that you can afford this trip and its not going to be one way journey. But that's not the only criteria.
I would recommend doing some research on this topic. Most travel agents wont tell you the truth upfront either since they will charge you for generating a file suitable for visa application and there fees will be due as soon as you submit your documents at Gerrys. Getting visa for Turkey is relatively easy, but its relative. Not as easy as getting a Dubai visa though.
As for your travel plans, check Accuweather for temperature estimates. I would recommend pushing it to March. Summers is not for us. Its hot and humid, so while it maybe an ideal weather for 'goras' you will be sweating like anything as most of sightseeing will be done on foot and in daylight.
Having said all of this, do go for it. It sounds like a wonderful trip and from my experience your travel through turkey will be a delight. Just do as much research as you can. I found TripAdvisor really helpful.
