Simply wipe all the guild's hours after that remake all the towers next make a guild cash system for basing add a actual guild house with meeting rooms and stuff like that and rooms for all the members and they can edit it as well and so shields can work during basing next and turrets next change the hp system.
And here's some improvements to the towering.
1. Lets say towers take damage over time and the damage affects how much hp the tower has so the more damage the tower. But it can be repaired you can buy tools with a certain durability and you repair broken parts by playing a minigame but if you were to get hit you would have to start over.
Next increase the member cap and tower size.
Along with the guild clash system make it so if you kick a member you guild let's say looses 300 gralts and it goes to the member that was kicked.
Next is to make the ally system have more depth. For example my guild was certain divisions for certain things such as a war tag and special services and stuff like that but what if you all worked together to get that 1k hat wouldn't it be fair for everyone to get the hat. Not just the ones on the main tag.