Getting a +5 pip reward for being in a zerg with +20 players would benefit organized zerg play and zerg players.
Ticket gain is mostly time gated.
Being a squad leader and being first/last in squirmish has little influence.
The latter is also not really influenceable by a single player, thus has little impact/reward on gameplay.
Outnumbered buff, however, gives +50% to +100% pip gain, but only benefits roamers on maps with low ally-count.
Such a bonus to be in a squad, not only people k-train and blobs would benefit but also serious public squads and organized guilds.
At the moment they effectively get a pip-penalty for not loitering in an outnumbered map instead of playing the zerg-part of WvW.
It would also benefit new players as well as veterans, as long as they are a member of a medium-sized squad.
Side effects would be randoms joining public squads more often. Even if they still scattered across the map, the added communication would actually help the public. Also, roamers would most likely form a map-wide-squad more often, just for the sake of the reward, thus being able to locate each other and communicate more easily.
Also the chance of being outnumbered despite having a +20-squad on map is pretty low in my opinion... but even then, since tickets are mostly used to gain armor and a full set takes multiple months of loitering around (base requirement) I think a small pip gain increase in those occasions won't have much influence there.