Jerk Disease,
I understand all that, however, you have to look at it from Luffy's POV– we don't expect him to CONQUER anything about the world, he isn't supposed to be STRONGER than the world, he's just the underdog.
Having this time skip to raise him up a few levels, which isn't mandatory since all he needs really is a way to defeat Logia, isn't worth it. Oda spent the early portions of the manga, the original ten year time skip, to suggest that Luffy did train in the past and had already been trained to the current level he is at. He doesn't need to train physically and stuff, he's naturally strong like that.
So, yes. Luffy is on a high-level at this rate, and he'll be constant until the end of the series since he only wins by LUCK, and he does it often. We don't expect Oda to have Luffy run around take over the world, Luffy doesn't want that.
All we expect is to see him mature, and grow. Furthermore, in order to make Luffy stronger, or near his peak, all Oda has to do is add Haki and then Luffy's pretty much set in stone, minus the obvious adjustments.
Luffy defeated Moria, Lucci, Crocodile, and Enel as his big time opponents.
Moria - Luffy was stronger, faster, and obviously better than him, minus the battle IQ stuff.
Lucci - Luffy's GEARS allowed him to surpass Lucci, otherwise, Lucci is physically stronger than Luffy [debatable] and he is surely faster than Luffy's base. Without gears, Luffy is on par, or slightly over Lucci.
Crocodile - aside from him being overpowerful with his DF, Luffy beats Crocodile in every category, except DF abilities… Luckily though, there's weaknesses and that's what allows Luffy to beat Crocodile.
Enel - once again, Luffy's better than Enel at everything other than speed.
Now, when you look at the Admirals, they're pretty much a pumped up version of Crocodile. When you look at Magellan, he's just a cheapass with his DF to protect him.
Luffy's physical peak is already at a level near these guys, he's just with difficulties to defeat them that are based off of natural reasons; Logia, DF power, etc.
Adding a Time Skip isn't going to change anything, it'll just add needless wasted time and a completely redone world which will have changed and we don't get to see it happen.
From Oda's point of view, he'll have to introduce SOMETHING to have people like Supernova and BB stall in some form or way, without changing the plot too much. A year is too much because by then BB would already be a PK on his own. By then, the world would already be screwed and the Revolutionary Army would be in action by that time...
That's a long skip, especially in a manga that has been consistent in the timing of its plot.
A time skip will just add too many loose questions to the plot, and inspect everything to get picked up instantly by the readers. It's not that simple. Naruto was a joke of a time skip; it wasn't really all that important in the first place. Nonetheless, the manga had a horrible beginning and stuff...
You'll have to ask:
- What's going on in EB, SB, WB, NB, GL, etc.
- What's happening with So and So over there…
- What's this and that guy doing…
- What has this guy been doing all his time…
- Why is this not happening, etc.
- etc.
It's just too confusing to pick up the story because you won't be spoonfed what really happens as it continues. Oda has already told us all this:
- Luffy made it through EB, saved stuff and returned 'em to normal. Everyone is safe and stuff…
- Luffy defeated BW, and they're in jail or in retirement.
- Luffy made it to Skypiea– where they stopped Enel and left the island in peace.
- Luffy met Tonjit and returned him to his place.
- Luffy did the stuff in Water 7, we know the circumstances of what happened after that.
- We know what happened with TB and we're currently seeing what's happening now, with the war.
To time skip now is beyond belief because it will basically just increase questions to what is happening around the world in distant places like EB and stuff, which isn't important to the current time frame.
You can't introduce all that stuff unless you bother to please the mind and answer all the questions; it'll lack, greatly.
So, suggesting that Luffy needs to get stronger to keep up with the New World and stuff– that's unneeded... What would be needed is if the crew had the same experience to understand what they need to do; which they did when they faced Kizaru.
Luffy, Zoro, and Franky/ Sanji should be fine and set to fight around the New World. People like Nami, Robin, Usopp, Chopper, and Brook are a different case.
Thankfully, we don't expect them to fight constantly by Shonen standards; Nami, Robin, Usopp, and Chopper, as well as Brook, don't have the big bad fights going on.
As long as Zoro/ Luffy/ and Sanji are able to manage, then the story doesn't need a time skip. Which, thankfully, they can.
The SH crew isn't supposed to be the strongest in the world, Oda dethroned that status already because he made it straight in his story that there will be chaos in the NW and the SH will be able to squeeze through all that panic and make it towards Raftel somehow.
They won't just waltz in there and sweep the floor like they're on or beyond their level, they'll fail and barely make it to the end... Remember, the story is to follow the dreams, not become the greatest ever.
Luffy's version of Pirate King isn't to take over the world.
Zoro's only trying to reach the level of a guy that basically chases rookies.
Nothing else is competitive from the SH crew.
So, there's really no need to do the time skip. Oda doesn't even have to teach Luffy Haki or anything, he can easily just play it off during a battle like he always does.