Have a look at the exploded views of the ego, in the 05/06 or 07 manual, then look at same view of the 03 speed. Look at the way the marker works, then ask me the same question.
Hmm...dont have the Speed to hand...what are you saying exactly?
I think your technical opinion, would be better than mine!
The way I see Ego's, is...they are very simple..very simple, mechanicly.
There is so little to go wrong in them...and to fix it, is easy..the entire mechanical part, comes out in one bit.
I think you are getting at the fact that the ego still uses a Knock open valve principle, liek a cocker...very like a cocker in fact.
For their simplicity and performance, I think they are excellent.