- In the other older ones, including OD&D, 2e, 3/3.5e did you use them?
Much of my bitd gameplay was BX/BECMI (with AD&D add-ons as we saw fit). For both that and AD&D, psionics was much like weapon vs armor, name level keep & commander play, or the comeliness attribute: the first time we were exposed to it, we got really excited about it. Then actual play happened and it ranged from relatively trivial to a pain in the butt to deal with (often with only the DM and one player really participating). And then it faded into the background until someone new entered the group, found the rules, and got really excited about them.
In 2nd edition psionics saw activity when each iteration of the psionic rules came out (with all-too-quick assertions that "look, they fixed the psionic rules!"), as well as when Dark Sun came out. I have to say that 1) the addition of a psionicist class really did help give psionics more of a 'role' and seem less like a footnote; and 2) an interesting campaign where everyone was supposed to interact with the psionic rules made more people put in the effort.
In 3.0, I think we noticed early on that the rules were kind of troublesome, but with D&D we were still used to balance being all over the place. The psionic warrior was a big hit.
In 3.5, I think we decided that they did all right. Psionics was just one of many expansion systems (one of the most supported ones). It was fairly balanced (honestly if the rest of the edition were balanced within the range amongst the psionic classes provided, it would not have been bad). Overall, I think people thought it a win, perhaps with some consternation as to whether these weird tattoo&crystal mages that
called wands dorjes and staves crowns were accurate to theme to whatever we thought psionics should look like.
- Did you like having them front and center in 4e?
It was an interesting departure and more power to them for making those choices. I don't love the idea of making monk abilities and psionics the same source, but that's personal preference.
- Does 5e have enough, too much, or not even close?
I don't think it would be horrible if there wasn't more mechanical support than 3-4 sub-classes. Totally new rulesets alongside existing magic hasn't had the greatest track record (otoh the playtest mystic was not a bad first try, the could have become something if they had kept going). That said, either way I think there should have been an expansion (or a chapter within a XGtE/TCoE-like book) calling those abilities psionics (optionally) and discussing the ins and outs of including psionics (thematically) in your campaign.