Are past lives overrated?
As with many things in DDO, the answer is complicated, and depending on the day you will get two very different answers on the forums.From many people who have gathered all of the past lives, you will hear that they are overrated and that player skill (both in how exactly you're running around the map/quest and in having the right feats and enhancements for that specific build) and gear are the main factors of being highly dangerous/useful in high reaper content.
From people who have gathered a few and felt that their game has gotten easier, you will usually hear that past lives contribute a ton.
In my experience of having played since '09 and having gotten all the completionist feats so far, is that it depends on what content are you running. Anything below level 20 I feel like a demi-god if I am running R1 or less, but after level 20 I have to pick and choose my gear carefully, or else I become mortal again. I have a first-life character sitting at level 32 and 'fully' geared it IS less powerful than my main when doing the same thing with the same gear but not by a lot. At cap, my gear gives me most of what makes my character dangerous or useful and my experience playing DDO is what lets me know that this specific combination of things from gear/feats/enhancements either stacks or doesn't stack or is useful or not all that useful based on my play style.
At the end of the day I just have to say that if all you want to do is run through lower-level content blowing it away with little effort, you can do that either by having a bunch of past lives or by lowering the difficulty. If you want to be useful at level cap, you mainly need a solid build and to spend the time to get the right/perfect gear for you. If you find that you want to ek out those final small bits of power at cap, then you have a long road ahead of you.
If you are a newer player, I advise that you just find out what you enjoy in DDO and do that. Too many people focus on past lives and turn DDO into a job/chore, then burn out and are never seen again.