I use CSV3 and CSV2- and 2 copies of APB1 on my Blockade Retrofit. It works out fairly well, actually, as I can debuff multiple targets while still maintaining a high damage output. And it lets me deal with spam very effectively, which- especially versus KDF, is a big issue.
Now, if i wasn't running APB, then I'd probably switch over to CRF3 or something similar, or even just 2 copies of CRF1 and a copy of APO3.
I do think that CSV is underrated- the damage output is solid across the board, so you're still benefiting from it, even if you hare hitting a single target.
As for TS3, I should note that TS does approximately 80-85% of the damage of an equivalent HYT.
Thus TS1 does 80% of HYT1, but does it to 3 targets. TS2 does 80% of HYT2, but does it to 5 targets. TS3 does 80% of HYT3, but does it to 8 targets, IIRC. Now, sure, where are you going to get that many targets grouped together? You may just be interested in that exta 20% damage against a single target as the case may be,
CSV and Torp-Spread used to be much lower damage dealers than CRF and High Yield, but CSV and TS were rebalanced many patches ago to bring them within 75% of their single-target counterparts. However, they both hit a lot more targets, thereby giving them much higher net DPS when engaging multiple opponents.
If you're doing PVE, CSV > CRF since your target tend to be rather squishy. Torp-Spread tends to be better than High Yield Torpedo unless you are using the new Romulan Hyper-plasma torp (since this thing spams lots of torpedoes already, it doesn't benefit as much with TS compared to HYT).