I think your points are valid. But rather than try to say what's right or wrong, I'll just post some thoughts re level progression.

1. The match up between characters is not the same at low or mid levels as it is at high level. So essentially you're getting more variety of match up. For example, you can fight necromancers before they can put you to sleep and scourge you while you sleep. Muters may not be able to paralyze you yet, assassins may not be able to assassinate you yet.

2. It's often easier to get a fight at mid ranks even with fewer people in your pk range, because they tend to stay put in one spot for longer. And they are often more vulnerable because they are distracted. That in turn means you have tactics to prevent being ambushed, or to deal with ambushes. At hero, the tactics are quite different because you are generally on the move.

3. Slow leveling can actually give you a chance to develop skills, relationships with other characters (from grouping as you rank) which can then create dilemmas later. e.g. You friend from grouping has just joined an enemy cabal. How do you relate to them now? If you just skipped to hero you'd lose the evolution of your character and its history with the other characters in the world.

4. I actually find ranking is too fast a lot of the time. There's stuff I want to do that has to be done before a certain rank, and it's hard to stay low enough rank to do it until the right kind of group can be formed.

5. I think I had something like 8 people in my midbie pk range the other day. Admittedly they were all thieves, assassins, and rangers. And over half were imperials, which brings me to my next point.

6. You sometimes get people bandwagoning/ooc groups piling into the same cabal as their friends. Because bandwagons and ooc groups generally rank up fast, they tend to (with some exceptions) affect hero pk more than midbie and lowbie pk. Even if there's no ooc coordination, you still get the same phenomenon at times. For example, of the 5 imperial leader slots, only 1 was filled, which makes a lot of people try to pile into empire in an effort to get those slots. Ironically, I suspect at least some of the slots came free because of people trying to get into scion.

7. There are loads of quests and areas to explore that give you more rewards if you are UNDER a certain level. Actually doing all this stuff can already be a struggle because you gain exp as you do them, and end up ranking up past the level limit too early.