Aegeri: I get that you don't like the Knight, but you're really wildly exagerating the one minor advantage the fighter mark has over the Knight's aura.
It's really not an exaggeration. The amount of times I've seen marks been the difference between a character being knocked unconscious and getting a full turn of actions is innumerable to count. I've run over 8 games of DnD and I've never once seen marks never contribute to a combat. Also you again ignore the point that mark penalties will increase to -3 when most defenders take the relevant feats. So marks improve, while the Knight just gets worse as monsters increasingly get better powers.
I've played numerous encounters now with a knight and seen them fail to contribute a single thing (protecting the party wise that is)
multiple times.
It will not result in a TPK before the Mage Beguiling Strands the entire encounter's worth of monsters adjacent to the Knight.
The problem is due to the Knights inability to hold those creatures attention,
the wizard is already unconscious and won't be beguiling stranding
anything. Followed shortly by the leader once the monsters decide to mob him next. That's uh, kind of the Knights problem when he can be disengaged
extremely easily. Unless we talk about a completely character optimized knight (Dwarf, Defend the Line - which really is an absolute must have stance - and worlds serpents grasp).
Incidentally, the knights immense vulnerability to forced movement DID get a party TPKed actually. The Knights complete inability to handle a blizzard dragons aura got the party wiped in the capstone encounter of my IRL game Marauders of the Elemental Chaos. The encounter features all three young elemental dragons from MM3. It's arguably one of the most brutal encounters I've actually made, but the actual party survived it after taking heavy damage (they had a PHB fighter for their defender). We had a discussion - much like the one I am having right now with you - about the Knight. So we manned up, made a knight and subbed him for the fighter.
Surely if you're right the Knight won't be a disaster? Bear in mind the knight wasn't a dwarf with the stuff I keep mentioning. I suspect it wouldn't have been anywhere near this sadistic if I had optimized it in the fashion I mentioned, but whatever.
For pretty much the reasons I already told you the Knight
was a total disaster. Especially when the Blizzard dragon decided to become his near permanent friend (you should look up the Blizzard dragon, it's misery on a stick for the knight). We quickly found that when a monster boots you away every round at the end of your turn there isn't anything you can do about it. I downed the controller first, then moved onto the leader (who got super unlucky to be killed by the dragons aura "explosion" effect), then the strikers and finally the little knight by himself was smacked down by the remaining monsters. On the other hand the Battlemind and Fighter we tried under similar circumstances got through the combat no trouble - as again, mark penalties
added up. Especially when the fighter left the dragons auras - meaning all their burst attacks (heavily damaging) ended up suffering a -2 penalty.
It's interesting to note that many times the mark penalty was
just enough combined with something else - like illusory ambush and disruptive strike. Very often the -2 meant powers like shield and staff of defense greatly increased a characters resilience, turning a certain hit into a very narrow miss. Without the mark the power hit by sufficiently enough that it wasn't going to be worth using.
Quite frankly, I think you have a very narrow view of how penalties can be used tactically to avoid an
amazing amount of damage. A penalty that sticks around is better than
absolutely no effect whatsoever. That's often the problem with the Knight. He can manage to mark a few monsters that lack forced movement powers or similar, or is rendered absolutely ineffective trivially. He honestly needs the advantage with the mark being 1/turn to remain anywhere near competitive with a fighter. Who is still superior in every manner.
You're not going to convince me the Knight is better, when my own direct play experiences show its crippling deficiencies mean it's simple to deal with. When a fighter takes Warpriest (or another permanent mark power that can grant OAs on something like shifting) the Knight is basically never competitive anymore. You can't argue with stopping all forms of movement trivially and a massive bonus to OAs ensuring you miss absolutely nothing. Well except for skirmishers that can leave without provoking OAs, but hey, at least they are still marked unlike what the knight achieves - which is something between diddly and squat.