I've been in this thread for a while now and the arguments against including TH3s really seem to strain credibility at this point. Many questions I have asked have, essentially, received crickets in reply.
Ultimately, I haven't read a single reason
why it's bad to lower your clan weight via the inclusion of a "low" TH, like a TH3.
This thread has carried on upwards of 24-25 pages and many of the arguments just assume it's bad and haven't provided much logic/proof explaining
why it is. It's a logical fallacy at this point.
Extending many of these arguments to their logical conclusion, it seems that the general sentiment is that if you don't bring your absolute best/highest TH, you're lowering your clan's overall weight and that's "gaming the system" & "unfair."
I don't think that argument holds much weight at all. The arguments against defenseless TH that could bully at/near the top of the war map held a lot more water than this current scorn held by many to those that lower clan weight by including low TH in their roster. What many seem to ignore is the very real drawback of including a, say, TH3s in your war roster
As explained above, you need to justify
why including a TH3 that has only unlocked barbarians (in your example) is unfair and gaming the system.
I think there's a much more solid argument against lopsided bases than including low TH in war. I don't think it's reasonable to lump them together.
Insofar as including a low TH in war, like a TH3, I think this is a much better descriptor:
https://en.wikipedia.org/wiki/Gambit