I wouldn't in hopes that you get a Lego. Your chances are tiny. If you have a good team right now to progress I would hold onto them for when you can do a fusion. You are going to be getting Skelletor. I haven't looked at his kit but he will be a Lego you can use while you progress in the game. 

If you do not have a great team I would pull them in hopes that you get someone like Coldheart or Geomancer but even then... they will come at some point if you are ok now. Right now it is working to get so that you can run dragon 20. 

Thank you. Temptation is strong but I feel I have the makings of a good team and will keep grinding for now 

Definitely do not pull shards right now unless you are planning to be a spender.  

I saved them. Just saw this weekend is 2-times everything so I'll be pulling for that.

You shouldn't spend them this weekend either. Generally, you shouldn't spend them at all, until you're ready to do fusions. You can get by just fine with the free champs you get.

Though of course it's tough to resist, I'll give you that.

Speaking of fusions  When i 1st started fusions were different i think you would fuse multiple champions of same origin into something now you have 4 major champioms you can get if you have the proper champions to do it.  I got relic Keeper from fusion but when is it going to change I have no interest in the other 3 options I'd like to get Dark Kael thru fusion or Sanctum Protector (love Kights Templars) ..