I want to know this too, and if there's more level tools, then I'm screwed :|

new tools will be added, i would save ur essence until we have a way to farm them

The problem with waiting is that chances are, there will be even better ones than whatever you are waiting for now, eventually, should you wait for that too?

Also, some player hypnosis, overly optimistically if you ask me but not impossible, that new tools would also come with better secondary stat, at least on par with red gourd and possibly better. This would defeat the purpose of some of the tool essence. And as long as they aren't selling tool essence, and ergo this would not impact their income, this remains possible. If they do start selling tool essence thou, we can be fairly certain that new tools wont have good stat as that would cause them to lose income.

And besides, if they release multiple red for each slot, and you forge up the best ones among those, there is the chance that, like they did to the gold, where they nerf those ones such that the best ones change, nullifying your effort.

As it stands, the game doesn't have a very good track record as far as ninja tools goes in terms of consistency, so whether waiting is.... questionable at best.

So personally, I think while it might be worth while to keep the most valuable ones, which is nin/tai, rest can be used as the benefit of waiting is unclear.

cn only has 1 more ti than we do, and they got that a while back, so waiting on that 1 ti should be fine as we dont even know if more ti will come out ever. the stats gained from the new tools in that ti are about the same as the stats from red gourd, so the essence are still better. though the new ti doesnt force us to replace all of our tools, so some we are currently using like red gourd are safe to use essence on

If you currently look at certain tools in China, some of the tools are spread across into several instances rather than limited to one such as brothers. Also, red tools also appear early than the kage instance. So it depends if Oasis changed which tools can be found in our server or it was a update to team instance in China much late into the game.

Even now the Gourd's gold stats are weaker than the essence.