Newbie here. Spent the last two nights reading this megathread.
Firstly, I suspect we're gonna have the same issues as with the proposed MOTU film on the MOTU forum - namely everyone will disagree with everyone else. We all perceive characters differently and they are portrayed differently. Iron-Man wasn't particularly highly regarded by some until the Downey Jr films.
I loved Nolan's Batman and hated it simultaneously for the same reason: anyone could do the training and with some money, pick up the cowl. The way TDKR ended showed Wayne leaving behind Batman whereas for me it was always the opposite. Yet the "grounded reality" of the film was enjoyable, showed Batman/Wayne's limitations.
For me, I agree with darklord - Batman's strengths are shadows, stealth, fear/psychology. He should be an apparition - emerged from the shadows and merges back. I loved the Arkham Asylum/City games because you could perch on a ledge/gargoyle, survey a group of thugs, swoop down, take them out and go back up. Going indoors was even better as you could pick off the enemy one by one. This for me was what Batman was more about. The suit needs to reflect this.
In the Nolanverse, everything was premade and adapted. I didn't like the suit and thought the cowl was far too big (or at least small neck). I understood the reasons for using a helmet and separate neck in TDK. But Nolan's Batman wasn't as stealthy as he could have been (Hong Kong scene was awesome), he didn't do as much detective work but had a lot of help from outside.
The Batsuit needs to reflect the stealth element. I would prefer the black look to blue but would accept a compromise to midnight blue (ideally between midnight blue and black) or "blue black" ie black with blue highlights. I've slowly started coming round to the idea of a grey suit but I still think it is too light and needs tk be much, much darker - maybe charcoal grey. Hate the idea of pants on the outside. Just looks silly and even MoS seems to have ditched it. I understand the area needs to be broken up but the alternative would be a coloured codpiece which just reminds me of the Schumacher films.
The belt - gold/bronze is darker than yellow and less obvious. It helps break up the suit. I preferred things attached to it a la BB/TDK rather than pockets/pouches. The logo is important. It needs to stand out or there's no point in having it - something that didn't make sense in the Nolanverse. I would stand behind the idea of a heavily armoured chest piece if it was a yellow/gold/bronze oval.
Armour - in this day and age, Batman needs it. I would argue for something similar to TDK's revised Batsuit. A close fitting bodysuit with armour platers in certain areas. The bodysuit and hence the Batsuit is dependant on the wearer and a larger frame would work better. Keaton's suit was my favourite but I echo comments about his frame being too small to carry it off properly. I didn't like the chest armour in BR for some reason.
IMO a lot of the suit's requirements/design would depend on Batman and the setting of the film. If back in the 60s, you could get away with spandex but in the modern era, it would need to be revised. If Batman is more stealthy, the colour scheme would need to be darker. I do like the majority of Arkham suit - bodysuit looks like armour, long flowing cape. Hated the really long ears and exaggerated gauntlets.