wow thats alot of questions,but here are a couple answers:
1)charger- maybe try a different usb cable?one thing ihave found is that they are not all created equaL. i have some that charge fast,some that charge slow,and even one thats so slow it causes windows to crash

2)gingerbread is simply an update to an OS. the biggest thing that makes it better than froyo is that it is much better at management. it closes down un-needed background apps and process much better than froyo,making it more efficient and better on the battery. there are other small enhancements as well.
3) rooting- you currently have mr2 wich is firmware#1.70.605.0. it is still perfectly rootable,however the root method will wipe all your data. youll have to re-download apps,and resetup your phone,etc. first you may need a basic understanding of the root process. heres basically what the 7 step guide does:
-extablished temp root,in order to re-write the mics image. this lets the phone install older firmware. normally this is not possible,and will result in a "main version higher" error when attempting the older firmware flash.
-flash old firware,where it is possible to gain permanent root and write the engineering S-OFF bootloader.
-flash a rooted version of stock firmware that contains clockwork recovery for manual rom management.
the prollem with the current guide is that the last step,is outated. the root process leaves you on old firmware,wich causes your phone to want to update to current firmware. the solution is to flash a rom right after(custom or a rooted stock rom) or to substitute the "upgrade RUU" from the guide with one that scary helped me make. its available here:
http://androidforums.com/thunderbolt-all-things-root/389462-custom-mr2-upgrade-ruu-new-rooters.html
if you are patient alpharev/unrevoked may come out with a simpler method that does not even touch your data. i have no idea when it will happen,and if it will be compatible with gingerbread. im hoping it will,as i believe it will be some sort of hboot exploit,and not the current method.
you have up until gingerbread comes out to make a final decision,as the exploits that made the current guide work have been fixed in googles source code and no longer will function. if you want to use the current guide,you
must do it before GB OTAs start rolling. if you accept the GB OTA,youre rolling the dice that alpharev/unrevoked method will work(hopefully its out by then and they can say one way or another if it will or wont) or that a new exploit will be found.
last and not least,the lack of responses. this thread title prolly doesnt make alot of sense to some folks,and the thread and your questions may be getting passed over. on top of that,the traffic in this section is prolly significantly less than what it is in the other forums,especially by folks with thunderbolt experience.
therefore,id prolle reccomend that you post in the TB forums for quicker and more answers... use the general forums for general questions,and the root forum if you have questions pertaining specifically to root
