I won't take them seriously until I see a game or game series that I can actually get into. Square Enix and Final Fantasy Dimensions, along with all the HD remakes, are an exception (though I don't really like them as much as the ones I've played on this site)

I feel like mobile phones are okay for smaller games, but not any much than that. Being a die-hard fan of the Sonic the Hedgehog series, find the SEGA ports of Sonic 2 and Sonic CD (My two favorites), really epic! The convenience of being able to pull out my phone at the doctor's office and play Sonic CD real quick is super fun and definitely worth getting. However then I look on the App Store and see that they've created mobile ports of games like Half-Life 2, Bio-Shock, or even the Telltales Walking Dead Seasons One and Two. Games of that scale should be left to either keyboards or controllers, I personally think. Maybe it would be different on a tablet like an iPad or something like that, but I just think that games like that can't be experienced to their full potential on a simple mobile device. I'm not sure though. Maybe that's just me...

They should, but only a bit. Phone games are getting massively popular and a lucrative industry, so there should be just a tad more attention.

However, a company making games for a phone should never go as far as micro transations. That's just a scam right there.

Casual games on a phone are fine IMO.
PvZ, Angry Birds, Cut the Rope, etc are very successful and have definitely got me thru some boring times. 

Developing exclusively for phones though, I think its a fad that don't last. 
It's not something to be dismissed right now though.