I believe that they could look much better given all the hype and supposed power of Revit.
So what exactly are you griping about? The look of them, or the functionality? Is the leader somehow not doing what it was intended to do or something?
They are very random both in distance of the landing, distance to the note and placement relative to the notes.
They are more than a little chaotic; which is exactly the users complaint.
Now one might argue, that it is 'only' a leader, and that would be a very thin justification for the user to not have more control over them. One could even question the accuracy of a BIM model being built within a(n) application wherein one can not control something as simple as that leader element.
Higgs, I definitely see your point and I understand where you're coming from.
However.... let me iterate the true meaning of using Revit MEP - it goes above and beyond CAD designing. CAD means computer aided drafting, in other words: an extension of the drafting board. CAD keeps the designer in mind, Revit has a much different approach. AutoCAD MEP is a very good tool in designing, but when AutoCAD 1.0 arrived it was nowhere near capable of what it is today.
Point being, if you are really going to harp on the look of a leader then I don't know what to tell you. The Revit platforms are still far from matured but we all know where it's headed and I will admit that I like what I see coming. I like being able to get virtual equipment and material catalogs directly from the manufacturer, with all necessary engineering data attached so running loads or calculating pump selections can finally not be the brutal and manual number crunching task it's always been.
I just feel when you say "given all the hype and supposed power of Revit" you are bashing the platform as a whole, not seeing the ingenuity behind it and surely not seeing what it might could be in ten more years. Hell, maybe that's Autodesk's fault... when they buy something up they seem to know how to screw it up.

Point is, if you have to look past a few things like leader styles then I say so be it. That's my $0.02 for what it's worth.