If your going for an MMO Mouse with buttons on the side of the mouse, make good use of them and use WASD to move in its place but still make use of Shift/CTRL/ALT Modifiers on extra hotbars to get full use out of every button on it. Example being my basic rotation and short CDs are bound to 1 - = which is my 1 - 12 on my mouse buttons, I use Shift for AoE rotation and Higher CDs, and CTRL for Major CDs that way I'm not hitting wrong things, but still can happen usually if my hands shifts from sneezing or something that causes me to move it more then usual.

As for your mouse hand, it comes down to muscle memory from practicing. Best thing to get that down better is to go to a dummy of some sort and practice just doing basics on it without the need of being in battle for at least 30mins to warm up before doing Dungeons or Raids, but if your just going to be out Questing during those times, then you'll be fine cause you'll build hand coordination between the 2 hands.

Biggest thing, don't give up even if it seems hard, I started out in 09 playing WoW as a clicker and I was so slow and bad but I didn't know cause it was easier back then, in 2012 I made the transition cause I wanted to PVP better and after a few months of practicing, learning macro making, it became second nature and now I can do the same thing with any game on the PC.

Another thing to practice for the keyboard is Homekeys. Learning how to type will let you have less down time typing out messages, and more time doing stuff. It might not seem significate but it's a big deal for quick effective communication when you have limited time. There are great tools out there like Typing of the Dead, and other things. Just do a google search and you'll find lots of things. I went to school for computer stuff and my GWAM was 50 which is above average, but not something extremely special either just really helps out and with lots of use you'll get it down with practice.

With Mouse, your Normal Camera will be Left click which won't move you, and Right click will be your movement facing. It becomes easier to turn that way, don't rely on the A&D keys for turning, it's too slow, and easier to get killed that way when you need to face another way. You'll be able to set your DPI with that logitech mouse, find one that fits your hand grip, arm length, and mousepad size. The lower the DPI the more it takes to turn, the Higher the less it takes to turn. The way to find the perfect medium is pick a number, then from the center of your mousepad, pan your camera to either left or right, if it makes a perfect 360 from center to edge then that is the best one to use, if it takes less or more then adjust the number up or down as needed.

Everything in the end comes down to practice, picking what works for you, and over time you'll develop a bind system that works for you. I keep similar buttons on the same keys. (Ex. Stun, Silence, Limit Break, Etc...)