With regards to glue-ins, Triplex, etc. Here are a few of my thoughts.
The '5-piece' bolts seems to be good for routes that don't see a lot of hard falls which means probably about 90% of the routes at the Pinnacles. Obviously, there are some very popular sport routes (mostly on DIscovery Wall and the Monolith) where people take repeated falls while trying to lead them. In these instances, it seems to me that the degradation of the hole, and not the bolt, is the real problem.
So, what can be done to keep the hole from degrading? I don't think using Triplex bolts are the answer. While they are more easily removed than the '5-piece' they are still basically the same design. And, since they are 12mm which is basically 1/2" there isn't much you can do if the hole goes bad. Glue-ins might be a better solution in that they use more surface area to provide holding power, but again, if the rock quality is suspect, I really don't know what you do when a hole goes bad.
Sure, you can drill out a 3/8" to 1/2", but what do you do when the 1/2" hole degrades? BTW, experience seems to indicate that you can drill out an existing hole when increasing the diameter by 1/8" or more. Rebolters who are trying to enlarge a 5/16" hole to 3/8" have found it very hard to drill(too much binding) and have had to resort to using a reamer.
What to do? What to do? Given the generally soft quality of the rock at the Pinnacles there probably isn't one solution for this problem. It might be as simple as moving the bolt to better rock. Or, drilling the hole from 3/8" to 1/2" might work, at least for a while.