After looking through the spoilers and checking the available removal creature stats, abilities etc. I came to the following conclusions.
Khans sealed will be slow, even by sealed standard.
Evaluating it based on creature stats is difficult, because outlast messes up the math. Players won't have a static board position relative to combat, even when they're topdecking. But let's look at what they do as a whole.
1.-Blue does not have a common flying creature costing less than 3. WIthout being an alarm signal, that's a clue right there.
2.-Blue only has two common flying creatures (without defender). Yes two. I counted them. I actually thought I had missed one.One costs three for a 2/1 but does have prowess. The other is a 2/2 for four. You won't be flying to victory with that.
Then you also have two uncommon flying creatures. A four mana 3/1 and a six mana kung-fu 4/5. So you can expect things to clog up a bit on the ground. So if you have removal, and you see something that flies? Take it down.
Blue does have a common unblockable 3/2. But it costs 5. And even if you morph it, you'll be skiping your 4 drop, or you didn't have one and you're not exactly going to the tempo bank.
(Quick aside, a rule was broken in this set. White has more flying creatures than blue, so I guess it's officially the color of flying now)
3. Mana acceleration? Yeah, no.This environment is starving on that side too. The only thing you get are the banners at 3 mana. Don't bother asking green for it. The few green cards that search for land (I count two, magic number here) put them in your hand. Yes, there's rattleclaw mystic, but he's rare. So don't count on it. So you won't be popping up mid to large size creatures earlier than development wanted you to.
4. Next, the other thing that tells you how fast a format is. Removal.
Black? Well, you have five removal spells there. Which normally isn't so bad. One is a 2 mana enchantment that gives a creature -2/-2. We can work with that. But it's an enchanment so you rarely will get any CA out of this. You have to do it up front and legit, after that, everything cossts 5 mana or more. Two at five mana, one at six mana, and one at ten mana. One of the five mana ones has delve, but I wouldn't count on getting a discount before turn 4 IF you're lucky. The other is a -4/-4 so killing big things is not going to be easy. And killing small things will be based on the luck of how many debilitating injury you open. So far, things are still slow.
5.Burn
Removing small creatures is usually red's job. But we still fall a little bit short. There is nothing under 3 mana. One burn is at three mana, one at four and two at five. The three mana one is
arc lightning though. So you can get card advantage out of it. But you might want to save it for a 3/3. Arc is not common though. So you can expect to pay 4 and 5 mana for your burn.
So playing small creatures and pushing them through early with removal spells is not something you can hope for. The cards available simply won't let you. And removal will be too valuable for you to throw it at a 2/1.
However, you should understand that this wasn't done simply to slow down the format (though that played a large part.)
There are two other reasons.
1. The mardu clan has access to white black and red. That's basically where ALL the removal is. So if they had made Khan's removal on par with most sets. There would be little reason to go with any other clan than mardu. It would have access to all the removal in the set. And even if other options would be underdrafted, your mardu opponents would still have the means to deal with every threat you had. Also, Raid would not really have a condition because you'd be blowing up blockers left and right
2. There is morph. If you put a lot of good cheap removal. Then players won't want to play with morph creatures. No one wants to put a bunch of grey ogres in their decks that will constantly be killed early before they can do anything. Morph hugs a lot of space in limited design, just like pairing did in avacyn's restored (that in my opinion was a badly designed mechanic)
6. White doesn't have much common fliers either
The cheapest white flying creature costs 3, and it's an uncommon. The only other good common fliyer is a four mana 2/3(Does have vigilance though)
7.There is only ONE multicolor common with flying. And it costs 6 mana for a 3/4. The best you can do is hope to pull the uncommon icefeather aven. a two mana 2/2 fliyer.
8. Morph. I don't think I need to explain that one. Morph was not designed to be fast.
So yeah. You may enjoy this, but it won't be over quickly.
Don't take this as meaning that Abzan will have an advantage though. You need to pull down your pants to use outlast. If you try to use it early, you may actually give a short game to your opponent. At turn five removal will start flying, and your tempo along with it. You'll have less threats in play if you activated outlast a lot, so you may not be able to recover from losing two creatures on turns 5 and 6. Or 6 and 7.