i want EVERYONE's opinion *spoiler* only if you have watched/read the entire sires

I disagree that the change is a bad thing really. The power increase and change in tone reflects a deep change in Luffy that had to come about following Ace's death. Personally, I find it endearing that his boundless optimism and confidence were so tempered, that he had to grow as a character emotionally as we'll as physically. In my opinion, the early parts of the series were really goofy, and it only became interesting when he started facing people who were more difficult and had to become serious. It's not that I don't enjoy the happy-go-lucky attitude he portrays, but Oda expertly made him grow up in such a way that he retains his personality but has changed his attitude. That's brilliant, in my opinion.

As for the power boost, it seems well warranted to me. It's showcasing the fact that he's become part of a whole new class of fighters, and the idea that he's suddenly become nearly unbeatable will be itself tempered shortly. They have to make him far more impressive, mainly because Oda showed us a very large list of characters before the time skip that were so far above him that his strength, speed and ability were nothing by comparison. The transition needed to be made, an it had to be dramatic. The Fishman Islan Arc was a large showcase of the strength he desperately needed to succeed in the New World, where he will face Shichibukai, Yonkou, Vice Admirals, Admirals, and any number of other incredibly powerful people that we don't even know the full strength of yet.

I can't say that I agree with that sentiment. I find it much more interesting, now that Luffy has become somewhat more serious and has become a much better fighter. I don't think any battles have been 'boring', I just don't think that any of the more interesting ones are set to happen just yet. I also have to disagree with your words: 'Luffys obviously more powerful he's got this in the bag'... That's not strictly true. There are still many other opponents out there that have had much more experience learning Haki, and that have much more absolute powers than Luffy does. I think the interesting thing about One Piece now, is that we will see how Luffy deals with these challenges and whether he is up to it, or not. Plus, I like the fact that his smile has changed... It was going to get a bit boring having that cheesy grin all the time... Honestly, I think that the way he smiles now suits him more... It makes him look a bit more serious and not so -uh- silly. And it goes with the new outfit. This change in smile merely represents the change that Luffy has been through... He no longer has his brother to look after him, so he has been forced to become stronger and more serious, so that he can accomplish his goal, without killing himself, or any of his Nakama.

If you keep watching into the punk hazard arc, it gets better; the battles and Luffy's smile

As far as I'm conserned, from the moment the CP9 arc began to just before the time skip, the one thing that kept Luffy alive throughout the whole thing is his 'protagonist syndrome'. He faced people clearly stronger than him and barely survived time after time. If he was just a side character or something, he wouldn't have suvived through all of that with just a scar on his chest (and, albeit, a deep emotional scar). If he didn't become the badass power house he is now, he would quickly be crushed by the New World, no doubt, just like Moria suggested. Granted, I'm not the biggest fan of the fishman island arc to be entirely honest, but from looking at the Punk Hazard arc, I'm not complaining at all. I mean, to be fair, we all know that Luffy is going to survive each and everyone of his fights, so I'm not really kept on the edge of my seat when I see him fight. Even with his epic power boost, though, he probably would have died from blood loss at the end of the fishman island arc. But his 'protagonist syndrome' activated and summoned the power of plot, calling giant sea king's down to catch Noah and Jimbei to convenient have the same blood type as Luffy so he can give a transfusion. I don't see how that was never a problem before. Luffy's a rubber punching bag--he should have nearly died of blood loss already several times, but NO, it only happens when it's convenient to strengthen the audicence's bond to Jimbei before Luffy asks him to join his crew. Then get refused. :/

Anyways, I digress. My point is, the power boost does not mean too much. Essentially, he went from the underdog to being on the same level as everyone else. Honestly, I think his bounty suits him more now, rather than him just getting lucky with outrageous events like Ennies Lobby and Alabasta. I'm happy for the others though. Ussop is finally closer to the sniper I'm waiting to see and Brook's devil fruit actually does something! :D