You're still going to play pretty much exactly how you were before, you'll just know the state of your aggro now. If you know how to manage it without the meter you'll be doing pretty much the same thing with the meter.

Also having the meter allows you to push the limits of what you can do without having to worry about pulling hate. If you know you've got a decent amount of leeway with the hate you can go crazy and try things you may not have been willing to do so before without knowing.

All this does is take the guess work and speculation out. The mechanics work the exact same way with or without the meter.