This will probably be an unpopular opinion, and I'm one that used to hoard every bit of gold I could until I had 30K to spend. I don't believe this is the way to go anymore, for various reasons:
1) You waste a ton of gold on things you wouldn't normally do. You'll likely blow through thousands on weekend boxes, legend boxes, etc, just for the sake of hitting 30K.
2) The players aren't generally worth it. A 20K tier 445 max guy just isn't that valuable anymore. The 480 max 2 skill legend is nice, but how many of those guys could you probably get if you spent the same gold on two WOH events?
3) After the weekend, you'll likely be short on gold for Monday, Wednesday, and weekday CvsC events when you really need them.
4) On your way to saving all that gold, you'll withhold from spending it in many situations where you could have really used it.
I feel the best way to go is to try to maintain a consistent gold balance of several thousand, build it back up, and feel free to spend all the time on CvsC to put you over the edge on getting MVP/high round rewards, WOH boosts, and other things that come around where you need gold immediately.