After some thinking I have come to the conclusion that what is wrong about the Ultras is that
a) they come across as supposedly natural born winners which makes them unlikeable and
b) them being the template after which the others are cut makes them a bit bland.
So here's my idea on how to fix that:
Stop making them natural born winners who almost effortlessly accomplish fabulous deeds. They may be successful and can accumulate much further glory but when they do, make sure that it is always the result of hard work - and not because they are innately better than all others.
Yep, that's my solution. Strip the excessive bling off of the Ultras and simply turn them into the hardest working Astartes in war-business. When in Deathwatch RPG something goes down, the Ultramarines are supposed to be the most thorough planners, the ones best prepared, those who have their gear in the best of possible conditions - because they spend pain-staking hours to clean and triple-check everything to leave nothing to coincidence. They have the background facts checked, they have studied maps in detail. This is something that other Astartes also do but make Ultras go above and beyond the normal calls of duty there.
And make them efficient, make them always focussed on the objectives of the mission (or alternatively the higher goal the mission is serving).
I wouldn't make Ultras into glory-hounds. Quite to the contrary, I would make them not care about glory primarily, I would make them care about the mission and ironically it is their sucess in serving this way that then makes them accumulate glory on behalf of the chapter. They never lose sight of what really matters in the big picture.
And they rely on the book because it contains the sum of millenia of wisdom - tried, tested and proven over and over again. They rely on it because it is de facto the way to succeed - if you know how to apply the wisdom contained properly, which they do.
This interpretation of the Ultramarines is certainly more appealing in my book than what we find in the current Codex Space Marines or the Ultramarines movie. And it also seperates the Ultras from their successor chapters which generally have lost focus of the essential to one degree or another.
Alex