In my area is the oposite. It's harder to get a group together for T4 T5 raids , so the majority me included is forced to do T1-T3 raids. So not a good idea for me:)
EDIT: Ireally like doing T3 raids cause its the only really challenging thing at this time in pogo.. Achieved victory over all T3 raidbossses except Ninetales and Confusion alakazam and its kind of satisfying to achieve this alone.