If want easy renown and fast medals, solo on a dps class.
If you want to carry your realm to victory and push the frontlines towards enemy capital, play a support class.
Once you stand at the gates of Loldorf, all the dps will personally thank all those healers who threw them out of party hots and send silver coins to all those brave defensive tanks whose HoldTheLine efforts allowed the whole realm to push together back the tides of Order roleplayers. Your internal realmpride level will also increase in the end, fostering new age of friendship amongst the true heroes of the realm.
well okay, we might lack a greater campaign purpose for now, but letting support classes get renown rewards from actually providing support to their out-of-party allies is something we had on live, and IMO functioned well. Maybe tweak it some, but the current system where even healing other parties in warband is not rewarded, not to mention throwing heals to randoms in lakes... doesn't really feel right either.
There is a reason why considerable amount of rr80s and rr70+ chars are DPS classes, with relatively less healers and tanks in the upper echelons.
It also feels wrong, because unless you are one of the few lucky ones who get to run scheduled party/wb, you will be among the vast majority of people who pug a lot, and gains from hour spent in lakes roaming can be immense between a well played solo dps class or a tank/healer who really tries hard to help their pug wb or aids soloers, but gains far less from it.