To start things off I'll bring up one of my biggest wishes. Dynamic Birthsigns. I know it may not sound important but let me explain.
In Oblivion I loved the idea of Birthsigns, they made you unique, they gave you cool powers but sooner or later I realised that the birthsigns were only a fraction of what they could be. As I got further into the game I realised that birthsigns were underpowered and a huge waste of potential. They weren't important anymore because you could do everything a birthsign could do and better with practice. Why even have a birthsign if it will be forgotten.
So I thought of this: Birth Sign Evolution. With every level up your birthsign will increase in power some way and for every ten levels you recieve a perk exclusive to your birthsign. This would dramaticaly increase a characters uniqueness and power at the same time. Fans of this great series like me do not want a weak, unimpressive character. We want our characters to feel powerful and original and I hope you guys at Bethesda do too and I believe this is a sure way of doing it. Not only would it be down right awesome it would add huge replay value and it would give fans like me a high I won't come off of for months.
An example of this would be the Atronach Birthsign from Oblivion. I loved it. I loved it. That birthsign made the game so much more challenging and fun but sooner or later I felt unsatisfied because I realised how far it could go and how limited it was. In Oblivion the Birthsign granted a bonus of 150 points toward magicka, no magic regeneration and a 50% chance to absorb spells which was great, it really was but sooner or later it becomes stagnant and stagnant is not good. It remains the same throughout the entire game and loses its flare because anyone can boost there magicka and anyone can absorb spells and as enemies become tougher you need more power to face them. The birthsign can supply that power in a way that only a birthsign can. If birthsigns had evolutions a sign such as Atronach could increase the effectivness of spells by a small amount every level up and every ten levels a perk could be chosen to do things like increase the percentage of spell absorbtion(possibly to 100%) and/or supply another huge boost in magicka capacity. Another perk would be the ability to learn how to use the spells that your character has absorbed. The end result would be terrifiying. A character that can absorb any spell thrown at him/her and throw it back ten times worse with no visible drain on his/her magicka supply. Theres so many ways this can go, it'd be a sensation.
I would really like to see birthsign evolutions in Skyrim it could make things so much more solid. I'd also love to see new signs as well. Signs like 'the alchemist' which makes potions made with alchemy extremly powerful and allows the player to mix existing potions with each other and stuff like that(Throwable poisens and explosives would be really cool, just like grenades from fallout) or a sign like 'the archer' that lets you do stuff like shoot multiple arrows at the same time, destroying enemys at close range(sort of like a shotgun, imagine three explosive arrows hitting a troll at the same time!) and/or let players target areas of the body like V.A.T.S in Fallout 3. I can think of so much more but I think anyone readiing this gets my point by now. Thanks for all the great games Bethesda keep it up, your games are a part of my life.