Once you get full-disassemble, since every time you disassemble something you get a percentage chance to reverse engineer, you can just breakdown and rebuild an item over and over again to (eventually) guarantee a blueprint from reverse engineer. Generally we wanted to disincentivize things that weren't much fun, and this didn't seem like much fun. Though there are obviously a ton of other ways to approach it. This is just why things are the way they are at the moment.
I still don't understand the exploit here.
If you don't have the blueprint already, you can't rebuild the item, right?
And if you do have the blueprint, there's no point in chain building and unbuilding it to apply Reverse Engineer, because... you already have the blueprint. The only things you can chain rebuild are things you already know how to build.
In any case I would like to ask that deconstructing things you built be at least added as an option in the config menu in the next patch. Even if it worked, the exploit you're describing seems extremely minor in impact to me, while the inability to deconstruct stuff you built basically killed the fun of playing a tinker for me -- I stopped playing them entirely once I found out, since I'd been picturing myself being able to whip up whatever I need and then deconstructing it when no longer necessary. Without the ability to deconstruct your creations (and, therefore, without the ability to build what you want on the fly without constantly hemorrhaging bits), I feel that tinkering is mostly a waste of time -- you're better off just trying to buy what you want directly rather than building it yourself. I don't think it's worth crippling the core functionality of tinkering for the sake of killing a minor exploit.
I mean... I think a much better alternative, if the issue is Reverse Engineer + Full Disassemble, would be to just make Reverse Engineer work 100% of the time when you have both Reverse Engineer and Full Disassemble. Why not? It requires an extremely dedicated character to get to that point, with a bunch of stat points sunk into Intelligence, and truthfully I feel tinkers are underpowered already. Most items you only need one of, so who cares if you get the recipe? For the others... the alternative is to buy a data disk, which wastes a bunch of money (which could have been spent to just buy the item itself), but conversely is really just a matter of grinding and lugging stuff to sell back via recoilers.
I just really really really don't think forbidding the disassembling of stuff you've built is a good idea. It makes zero logical sense and isn't indicated as a rule anywhere in the game, even though I'd consider it a defining limitation for tinkers that alters the entire way they play in an unfun manner (the first time I saw it I assumed it was a bug, and it continues to look and feel like a bug to me even now that I know it's intentional).
If nothing else, look at it like this: Even if there is an exploit related to chain-deconstructing, it's only going to ruin tinkering for the few people who discover it, decide to exploit it, and don't enjoy exploiting it. Removing the ability to deconstruct items you built cripples tinkering for
everyone -- I seriously think that it's something that every single person who plays tinkers long enough runs into in an unpleasant manner. That just doesn't make any sense as a solution; by removing the ability to deconstruct stuff you made, you've taken a minor problem with tinkering, one that only affected a few people, and turned it into a major problem with tinkering, one that affects everyone.
(Though I'll repeat, unless you're misstated it or I'm misunderstanding something, I think the exploit you're describing just isn't there -- you can't rebuild stuff unless you already have the blueprint, in which case you don't need to use Reverse Engineer.)