Useless spamming will not work either in small team PvP, even with unlimited gem use. Spamming stupidly gets a person killed, especially if some of these classes cannot heal spam with pots and stuff.
You want people to play with strategy, give them unlimited use to items like gems and AD and other catalysts, otherwise the classes who use said catalysts will never show up for these events as they won't be seen as the most viable options