Ok.
Blaze can be played as main tank, solo tank (in right drafts and good communication) and as second tank.
Blaze has good sustain, HP pool and a lot of tools to absorb damage (healing, armor, shield, unstopable, Bunker, magic armor), but he lacks hero damage, so don’t expect to kill someone fast.
He has good waveclear by AA, Q, Q+W.
He has good zoning by W, Bunker or Combustion.
He has AoE skillshot stun, what can stun multiple targets. Can be used to engage or retreat.
He is vulnerable to CC heroes, like ETC, even with unstopable. Be careful.
To engage, use W to slow target and immediately use your E to stun it before it leaves slow area.
Don’t ignite W by Q or your AAs (if you took Incinerator Gauntlets on lvl 7), if you want your targets to be slowed, because your W doesn’t slow when it’s on fire (until you took Adhesive Petroleum on 4 lvl, what allows you to slow by W even if it’s ignited).
Your AA is AoE, so attack middle minion to damage sided minions too.
Most your talents and builds are good. Be free to experiment!