TC14-18 seem to be the most useless of all TC levels. Most of TC5-9 I haven’t even bothered doing the research on yet, but I’ll admit they do get occasional use. Right now I’m actually running TC7 to max out Brienne’s skill for the next raid tournament.
Why oh why couldn’t they include 4* heroes in TC14-18? I think they would get a lot more use for filling in those colors we are weak in or for those unlucky players who haven’t got Wu yet.
Problem is at the point you get your base and TC to these levels, you don’t care about 3 stars anymore. Not at this training time at least. There is no way this could work. Adding 4* to the randomizer would be good idea to ressurect it. But then they’d need to at least double the training time to keep up with the standards.
I have been planning on posting this same question for a couple of days, as I’ve been burning up time and food researching these levels (on my second TC; went straight for level 20 research on the first). I assumed there must be some good reason for doing it, but after seeing that the training time is a full day, I’m struggling to come up with any reason you would use these. Anyone? Anyone? Bueller?
Short answer: no. There have been several proposals to repurpose these levels for more useful functions, like training troops.
Ok, what if… you decided you desperately needed the loot from the rare tier of a challenge event but hadn’t levelled a 3* of one of the strong colours and you’ve got loads of feeders saved up but otherwise a really short time frame to prepare?
Maybe in 2 million players that’s happened once?
Short time frame meaning time to wait a day for a probable 2*?
Yes…but you really, really need that loot so it’s worth a shot. It’s the compass you need to ascend GM and your alliance is switching to red war tanks and you’ve got 200 Barbarian emblems ready to go.
Could happen to any of us 
If you dont have any 3* heroes like me. You can probably use them to at least get 1 of each color for the tournament perhaps. 
I have right now only stronghold of LV13, but from how the things are looking I think I won’t research LV14-18. Just like I did not research LV5-7 and 9 (I did Dark research because I needed to Max Rigard’s skill ASAP). Better waiting extra day and have sure 3-star hero or even 4-star one.
I use TC14 four times because at that time, despite having nineteen 3* and three 4* heroes, only one of them is red.
Of course I don’t use it anymore, though I am tempted to use TC15 to get Valen (the only classic 3* missing from my collections)… But I think it will be better to wait for him while training using TC20…
Edit: Finally got Valen, my classic 3* collections is complete so I will not use TC15.
Valen is a beast. I have mine at +18, 30% Revive. He has come back many times in raids and titan fights. Having him on 1 hp and then firing Kiril= 
Best case scenario for me would be making TC14-18 color specific versions of TC13. I would rather see another building for troops.
I’ve only used them by accident before, never really found them useful though. The odds of a 3 star hero are quite good when you get them, but as discussed already, by the time you get to them you already have TC13 and there’s no point to not do that training instead.
I believe these TC levels should be changed to do something else. Some suggestions I’ve heard:
Those are just some suggestions I’ve heard myself to make these training levels more useful.
Related: Training Camp - REDESIGN PLEASE
There is a master thread there with a list of different requests. Personally I think all levels are fine, except for 14 - 18 which I expressed my thoughts about them needing to be more useful.
Ooo. I like all of these ideas.
I did actually research 5 - 9, at the time I found them useful, and I still find them useful myself for powerleveling heroes of certain colors. Despite their high cost the time it takes to get heroes is quicker than TC11, and you’re guaranteed to get them in that color and possibly as 2 stars, unlike TC1, TC2 or TC19.
See that’s what I mean. I can’t even justify TC 14 - 18 just because 1 day is way too long for a possible 1, 2 or 3 star hero. Even if it is a 3 star it’s still way too long.
TC2 gives 1 and 2 star heroes
oh sorry, what I meant was that TC1 and TC19 don’t give 2* heroes, and that TC2 doesn’t give heroes of a specific color you need. I realize now that I was unclear when I wrote that 
Yeah, that’s the reason why I did the Dark research in the end, to grind Rigard’s special. Those have their use, since 1h training gives you 1-star or 2-star hero, while TC14-18 give maybe 3-star hero per day, which is as slow as Guardian Owl’s special. In other words, less than ideal for training - which would be its only purpose given that TC13 guarantees rare and gives a shot at ‘‘l33t’’ hero.