i suggest to remove merit and crystals from towers
Not going to happen. You can "suggest" this as often as you wish to. And we will always repeat the same answer.
Siege War is an "entire guild" thing. If your guild is unable to find a consense in gaining what is needed, you might play the wrong game. Everything that is coming from you is entirely for your very own benefit, but you are playing this with a group of people, who do deserve something for the assistence they bring to a Siege War.
If it's not the merits, then there must be something as replacement. Don't only use your guild. Assist each other. After all they are the ones bringing in the most merits for the upgrades needed to enhance your abilities during each and every Siege War.
If you remove their reward for assisting you, what's the point for them helping to get the upgrades? Right, no point. You would be on your own.
It's like a clockwork where everyone has got their task and if you take their reward, you shouldn't get any either.
Tower guards are easy to defeat, been there done that.
It's all about the support of each other and working together. If that's something you can't do, this entire conversation is pointless.