You don't have to justify an opinion, are you crazy? Next you'll tell me my favorite color can be either correct or wrong =/
On the other hand, if you continually claim something which seems to the majority completely incorrect, you best be able to explain your reasoning.
e.g. If I say "Spain are terrible at football" and people say "hang on, they have a lot of excellent players and won the world cup and European cup... How can you say they are terrible at football?", I'd be expected to justify my opinion. If I can't, it would be reasonable to assume I'm talking nonsense. If I then go on to say "I'm right, I'm right" with no reasoning, I just look arrogant - especially if I then criticise others who are using reason and valid arguments.
Anyway, moving on, what do people think of HOTS? I don't really see much Terran atm (2/3 of people seem to be Zerg and maybe 1/4 Protoss :-/ ) but my opinion on the units I see:
Tempest: The uses I see for it most often are trying to force the opponent to engage by constantly picking off things with 3 or 4 tempests... Really annoying to be against but I guess it's your fault for letting them build them.
Swarm Host: Similar to Tempest's role.... really similar, but maybe better for massing up a little bit more and useful earlier in the game. Crap defense.
Oracle: Can be a pain but haven't seen them used too well yet...
Mothership Core: Good for recall, makes early harass with just a few units FAR less effective (IMO too much so in PvP, not sure about other races)
Haven't really seen the other units used too much, but haven't played a massive amount of games. The maps feel really different to SC2 too... far more 'different routes' kind of feel, and of course, plenty of destructible rocks