Narced Out -- some free advice from someone who has absolutely no axe to grind in this matter.
a. The quesion, "What do YOU want out of diving?" is a very good one. If you want to become a skilled diver, then you need to work on your skills -- easily said, not so easily done.
b. More "recreational classes/training" vs. the "intoduction to technical training" route (i.e., Fundamentals or Essentials) -- The problem I see in too much of the "recreational" training is that the instructors are training people up to their level of training. They may have a lot of training and/or a lot of experience (but not necessarily!) AT THE LEVEL THEY TEACH. However, their "world view" of Scuba will be limited if that is the case (or may well be limited). That is why people are suggesting Fundies or Essentials -- because those instructors are teaching BELOW the level of their training so their "world view" of scuba is generally broader.
I am not necessarily a fan of taking more classes as opposed to taking more instruction. A class might not be what you need whereas having more specific instruction may make all the difference in the world for you.
You mention your Sac rate is 0.8 (I'm assuming cubic feet per minute) -- which is, quite frankly, not all that great for someone who has done 25+ dives (with a fair number of classes). I'd be willing to bet your balance and trim are off which means you are working harder than you need to work. There also may be some issues with your gear setup that is also making you work harder than you need. While getting into the "right class" might help you here, I'd suggest looking into hiring a "technically oriented" instructor for a dive or two to work on YOUR specific issues.
If you went into Fundies (for example) you'd be introduced to several things that, while nice, may not be all that relevant at the moment (learning and practicing S-drills, no-mask ascents, etc.) when you need to spend more time on something else (perhaps balance, trim and perhaps your kicks).
As someone else wrote, you seem to have the right attitude -- now you just need to find the right person to get you over this hump and to a "higher" level of diving.
