As a preface, I play a lot of condi weaver and tempest in fractals.
Firstly, Catalyst got some issues. The first thing I noticed was I never got to use the jade sphere. For a spec centered around combo fields I don't think I used any combos at all because of how difficult it is to get a field in hammer. In contrast, as a condi tempest, I'm blasting fire a whole bunch and just pumping out might.
Secondly, damage is just not there in hammer or in any weapon really. Hammer earth 2 gives what 5 stacks of bleeding for a 3 1/2 second channel? Dagger earth 2 gives 6 stacks in 1 second. It's severely lacking to say the least. Need to up those condi stacks up in hammer or else you're just better off running scepter or even staff as a condi option.
To add on to that the traits don't do much. Part of it is definitely how terrible jade sphere is. Traits could definitely be improved to give more damage, conditions, or something else to make it competitive with weaver and tempest.
As it stands I see no reason to use another weapon with Catalyst. It doesn't offer anything useful to existing weapon sets that doesnt already exist in weaver and tempest. If you wanted to play condition staff, weaver and tempest are okay for that. If you wanted to play power dagger, you've got air overload to carry all your damage and you've got some cool dual attacks in weaver. The same can't be said for catalyst.
That being said I do like hammer 3. If the numbers were tuned on it, I can see myself slapping pocket raptors with a bunch of condi. Also the hammer animations look cool at the very least! That's all I got