I have been thinking about this for a while and I (and probably every even semi-decent player) will tend to only raise AA/KK/QQ/AK from the first 3 positions at a 9-10 handed NLHE cash game. Some may invlude AQ/JJ but no-one raises as many hands as they would from LP.

This means:
a) you get a lot of respect for your EP raises and too little action
b) you are often giving good implied odds if you open for 3-4bb UTG with a 100bb stack and aren't going to like folding postflop.

If you get to the stage where you are playing $1000NL+ and the player base is significantly smaller and even some of the losing players will be observing you carefully and using PT this is going to become exploitable.

What I have started doing now to try and balance this is raising hands like 33 or 67s from EP every so often to mix up my play.

How about if instead you never raise any hand from the first 3 positions. Limp with pairs like 77 and also AA/KK/AK. If the pot is raised by anyone in LP you can come over the top and either take it down or build a larger pot preflop.

If the pot is not raised obviously you will need to be able to get away from the hands easily on bad flops to a lot of action and you do lose some EV by not having raised, but the counter is that when you have limped with a small pair UTG people may be less invlined to punish you for limping and you can bluff from EP on a lot of flops repping KK/AA.

Thoughts?