What went wrong?

Only going to 193º is most likely the reason for them not being as tender as you would like.  Although there is variability, I think you will find that most pork butts need to get to 200º or so for tenderness.

I coat mine with yellow mustard before adding the rub, and cook at 250.  Finish at 200 internal and/or when the bone will pull free easily. 

xanderbbq said:

... As far as tenderness, they were ok, but they needed a little work with the bear claws.

That proves they weren't done.  Some things you cook to temp, but some things you cook to tenderness, not temperature, and pork butt (and ribs) you don't pull off the grill until they are demonstrably tender enough, regardless of their temperature.  With ribs you use the bend or toothpick test, but with pork butt you just probe them and you keep them smoking until the probe goes in "like buttah," as they say.

I strongly agree with @Hungry Joe that I just get better results at a dome temp of 250° or higher.  I usually aim for 250°-275°.  I feel like I get better smoke flavor, and that 200°-225° might be best for an offset stick burner, but it's too low for my BGEs.

As far as wood chunks, everybody seems to have different methods that work best for them.  I've tried scattering chips throughout the lump, but it didn't work as well for me as bigger chunks, a few deep and mostly central, and a few on top sort of radially around the center.

Again, I think the biggest issue in your cook was that they weren't done, as demonstrated by the fact that they didn't pull easily.  With the dome temp as low as you kept it, they probably would have needed longer than 7h.

xanderbbq said:

Thank you all for the information.  Next cook I will go between 250-275 until an internal temp of 200-203 (if it passes the probe test).  

Any ideas on how to get a better bark?

you'll have better bark after cooking it that long.

sugars in the surface of the meat, proteins too, need to carbonize (and no, to the sticklers, that's not the same as burning). 

some folks get more of that by using more rub, binders (mustard), and making sure there is some sugar in it.

but you will get a drier darker surface from just the extended time required to hit 200-205 internal

With regard to smoke I'll tell you what I've experienced. When my dome temperature is below 250 I get very little smoke. What I mean is that my wood chunks actually stop - or at least drastically reduce smoking. When I bump the temps to 250 I start getting smoke again. 
I don't know the thermodynamics. I do know that time and again this is what I experience. It's also easier to keep my egg at 250 and above than at any lower temperature. For those reasons I never try to cook below 250 degrees.

Just go a little hotter and be liberal with your rub

finished temps are nothing but a guide.  next time thou cook turn the temp gauge away from you when you stick the butt and ignore what the temp is and when it probes like butter then it's done......temps could be anywhere from low 190's to 205......it will "let loose" when it's done and you will be much happier with the end product.  

I agree with above, a pork butt can handle a lot more heat and at 225 it will take some time.  With large cuts of meat like pork butt and brisket you are going to have a stall that could last for hours.  I cooked a brisket over night Saturday into Sunday and it was in a stall at 153 for about 4 hours or so.  Went to bed at 12:30 when it was 153, got up at 7:30 and it was only 163.  Now the egg had gone done from 235 to 205 over night so I opened it up and got it to 265-275 to get it done.

As for more bark, use a binder for the rub may help.  I mostly use yellow mustard, don't worry you won't taste it or olive oil then the rub.  Injecting can add flavor, but can slow the cooking process down especially if you are cooking at 225.

I agree you need to put your probe in deeper into the meat to get a better reading.  When the meat gets to 195 is when I start probing.  When it probes like butter it is ready to be pulled.  Let it rest for for 20 minutes or so before you pull it to let the juices come  back into it.

Another thing I like to do with with pork butts is pork burnt ends.   You take it to 165-170, pull let it rest for 20 to 30 minutes wrapped in foil.  Cut it up into 1" cubes, put them in a pan with some sauce and put them back on for about 2 hours.  Stir them about every 30 to 45 minutes.  I like doing this now more then pulled pork.

Your cook looks good and like others said taste is most important.  We are all our own worst critic, I am on my self.