I agree with sed, theres got to be some middle ground here. Raising the hell out of people preflop will make them immune. Especially on micro's where you can put in a 5xbb raise preflop and get literally 4 or 5 callers no matter what. So raising this big will not narrow down the field. Going all in will only get the good hands to call. You aren't left with many options if you do a lot of big preflop raises.