Blaziken deserves investing?
There’s actually a reason to power up it?
Answers
What I do is try to capture the highest IV Torchic that I can which is at least level 33. You have to hunt for them when they are weather boosted. Thus, even though I hatched a 100% Torchic from an egg, I haven't evolved it. Instead, I evolved a 91% level 35, and will likely never power it up, because I want to save stardust for other mons.
Not really. It's an ok fighting mon if you lack Machamps or Hariyamas but at this point, how many players who have a Blaziken lack Machamps or Hariyamas? It's a good counter to Registeel and Regice, but Moltres, Entei and Flareon are all better.
If you just like Blaziken, it's good enough that you should be able to use it as your fighting mon and not feel too gimped. The kung fu chicken is kind of awesome so go for it if you enjoy it.
I've had raids where it auto-selected my double fighting Blaziken 96%IV over my Machamps (these are all maxed out 90+IVs). Blaziken is a little bit of a niche, but adds variety. Damage per second on Counter/Focus Blast Blaziken I believes exceeds even Counter Dynamic Punch Machamp (not as tanky though and its a one bar charge move for Blaziken).