A standard raise?

Looking for a little feedback...Ive been using a standard opening raise on my 6 man no-limit tables of about 4 times the BB. I will use this size raise when im the 1st in a pot, regardless of it being AA or 88 or AQo. Also regardless of my position. Is this the right play? Should my opening raises be mixed up some? maybe twice the blinds in some cases to 6-8 times the blinds in others? Ive had moderate success with this strategy, but trying to improve my game.

[-Skeme-]

I use 4xBB+1BB per limper. You might wanna reduce that to an initial 3xBB raise for 6 Max, though.