Total Deathwatch comes to 535 pts. Using less can save you potentially over a hundred points.
If I understand the objection correctly, it is that the options to field the Deathwatch seem noncompetitive right? You can only field them as a single unit OR as their separate units. Which means you end up with four single models that cannot join units.
Alright. My brother and I were examining this problem last night and we've come to the simplest solution we can. The Deathwatch are an Inquisitor faction set of units, and as such can be allied to any Imperial force. Our immediate thought was Astra Militarum. The Donatus squad can run quite comfortably on its own, all of them are able to advance and shoot and the unit has a good mix of ranged fire options as well as decent cc ability.
Cassius and Natorian are both independent characters, both have their typical unit type rules and special issue ammo. There's no real problem here, they can both join any Imperial unit they want or need to.
The remaining four present the real issue here, however they do seem to be designed with a degree of synergy in mind. Suberei on a bike with a teleport homer is an obvious link to Branatar's terminator deep strike.
Setorax honestly seems like the only one capable of really making any headway on his own, having a +3 to his cover save on the first turn and +1 from then onwards, as well as the ability to jump in movement and assault phases.
Delassio seems to be the most useless. No special cc gear and a lower tier version of a weapon already carried by a more resilient member.
So what did we decide? Easy. We're just not using all of them. Squad Donatus and most likely Natorian will be added to his Astra Militarum as an allied contingent. With an elite slot it is possible that Setorax will be used as well, but when run outside their formation it is not essential to use them all anyway.
Meanwhile, we have models that can be stand ins for other models in his space marine army. His most common opponents are my tyranids and necrons, so it's easy to justify a Deathwatch team being split among his army to provide support and advice. They would look Deathwatch, but just count as members of those units. If no units of their type exist, then they can be counted as characters. In this way none of the models are wasted and having at least one or two actual Deathwatch units helps keep the theme.
Nonsense is our Salvation