Too be quite honest, to have a server stuck on one version would hurt its popularity. Minecraft will continue to update, and speaking of which, there's already a snapshot in the horizon for 1.10. Herocraft has to update, or it will be stuck in time, with new content never being added. I have heard rumors of these plugins that are being worked on, such as some 'jitter click' plugin which may negate the 'slow' combat that people have been complaining of recently. Do not panic, from my experience, Herocraft continues on making good decisions, which further improves the quality of the server. Such as the entire improved dungeon system, and introduction to quests.
But, I would like to add, the lag has been getting worse. It's sending me into limbo every 5 minutes, to where I'm afraid to fight anything in dungeons because I keep getting kicked in the middle of the fight. So I hope this issue gets resolved, it's making my friends leave, and I'm desperately trying to keep them interested, and assuring them the lag is only temporary.