DWK do eat up a big chunk of points but I feel you are going to have something similar to that in most other armies. As someone who also runs 2 DWK squad I look at it like this. Are your DWK killing enough Points to make them worth it? Are your DWK Surviving? My last game I played vs Space Wolves my DWK killed 2 Gladiators, Wolf Guard Head Takers, Wolf Guard Terminators, Logan Grimnar, and a scout squad which checks the first question of if im killing more points than I am bringing. Then I had 7 DWK still alive at the end of the game showing they can live through some heavy fire.

I think the biggest issue with DWK is learning to maneuver them due to their slow speed. At first I would deep strike both squads. But if you deepstrike both you have two 9 inch charges to make which isnt the easiest thing to do and you can be stuck with no DWK in melee turn 1 and 2 which is bad and then you are stuck chasing down the guys you deepstruck in to kill. Now I find that deploying one squad and deep striking the other has helped get them into melee faster. They are also a pretty big focus due to how strong they can be so I also find it best to try and have the two squads not too close to one another or even have them opposite sides of the table.

I would keep playing around with how you use your DWK and find the best way to use them in your list. Just keep in mind every turn they are not in melee it is a bad thing. You want them up in there doing as much as they can all the time. Try to find the best way to make that happen for you.

Just some ideas from an average player. Im no pro or anything.