I would put my gem spent to date at around 10k+

Aside from getting over 7k+ stamina to craft all my judgement gears and level up to 110, I received 1 leader card, 1 Aphro card, many many 20mil coins, a few lvl 7 chips, about 8 x maria cards, a ton of purple cards, multiple 99 stars, multiple 10 purple stars, 5 purple stars, and made probably 20 lvl 4 chips from all the level 1 and 3 chips I received from the chest. Massive credits, and rep gained, etc.

My conclusion on the Casino is that it is worth it if you have disposable gems. If you want to maximize on your gems to power up, you can do a lot better. You can buy for example 100 stamina for 20 gem 5 times. You can buy the stars on Fridays to maximize on star gains, and Tuesday Tavern for saints.

As for the scroll. I have not hit it and I think the percentage set is so low, maybe 1 person will get it after a month. Even if they do, it replaces your current skill. Also there may bee other higher scrolls coming in the future.... I mean this is your main hero which should be the toughest hero in your formation. Greater savage IMO is not OP if you lose your current skill. It just makes you into Lance with a bit more power. Main leader should have the most power.

Also the scroll you get is random. So no guarantee after spending a ton of gems, you would even get the scroll you desire.

What they should consider is making the scrolls for your main (which can be changed multiple times) obtainable with fragments (100 frag for level 1 scroll, 200 frag for level 2 scroll, 500 frag for level 3 scroll, etc).