At SynCaine’s suggestion, I have been playing Boom Beach. Because most of the guild started playing about the same time, most of us hit the same wall at the same point: the PvP system in the game discourages playing. It is a variant on the problem seen with Marvel Puzzle Quest.
PvP opponents are matched via “victory points.” Victory points are acquired by clearing NPC bases and by successfully attacking in PvP; victory points are lost by being unsuccessfully defending in PvP and for having uncleared NPC or PvP bases on your map. You get more bases on your map (to clear or leave uncleared) by expanding your map. PvP is used to raid other bases for resources; one successful attack, and you clear the base off your map and take some resources. Sometimes clearing an NPC base will award an extra victory point.
Your goal in gaming the system would be to be the highest level player at your victory point level. I intentionally avoided expanding my map for a while to avoid the temptation to clear more enemy bases. For a little while, I was clearing every base and advancing quickly, which is to say I was flying face-first at a wall that matched me against a PvP base 17 levels higher than me. Clearing bases is good for getting small amounts of resources, but when you start getting raided five times per day, your resource situation becomes a bit more perilous. Of course, if everyone games the system, we are back to the same problem just with fewer resources in play.
So for the past week or two, most of the Boom Beach guild has been slowing down. Leave NPC bases on your map when they pop up, avoid PvP, fail at PvP defense and watch your victory point total get knocked back down to “reasonable opponents” level. The daily reward includes an incentive to have more victory points and you want stronger opponents because they’ll have more resources, but the gain per victory point seems small and stronger opponents are only good if they are strong but not stronger than you.
And now back to gaming matchmaking systems in F2P games. It is legitimately difficult to design a good matchmaking system, particularly in an environment with free (and large scale) entry and exit.