One last idea I had in favor of trustless masternode pooling, is that it would open up the possibility of existing masternode holders to offer shares, and let people pool with them. For example, if you run 10MN at this time, you could offer 20, 500DRK shares, and run 20MN instead. I would do this and not even charge people anything but just server fees so I could get more coins out of circulation. Since is trustless, and the shareholders control their own coins I would carry no responsibility. With this same rationale you can also offer smaller shares, and actively promote your masternode pool and charge a small fee just like mining pool operators do. I would not dare to do this right now because safe keeping of other people coins is too much responsibility for me, but would happily do it if the option to do it trustless exist.
So yeah masternode count could go substantially up with the creation of masternode pools just like mining pools currently exist. Is actually exactly the same thing joining resources together for a common goal. Miners can take their hashing power to any pool they like, masternode share holders could take their coins to any masternode pool they like too if it is trustless and they keep the control of their coins.