For WP versions in the past have there been mods done to them by the community to allow for things that otherwise wouldn't be possible. I.E. Mod to allow more then just the stock keyboards? I'm not very familiar with WP world so thanks in advance.
No. WP8 is not modable to the same extent android is, so custom ROMs are usually ignored. A custom ROM might get you WP 7.8 a bit earlier, but that is about it.
Microsoft has taken the Apple approach of locking down the OS and devices, but went the Google route of mixing in plenty of manufacturers in the process. What you get is a relatively seamless transition from device to device with sprinkles of customization or added functionality exclusive to the handset you go with. Example - the HTC 8X has Beats Audio.
Don't buy a Windows Phone for the customization and modding.
I came from S3 & I5, while I do sometimes miss the swype feature of android I have to say the predictive text / correction and the keyboard are very well designed, I seem to text faster on this phone then I ever did with swype.