Yes, leggo books are really valuable for me still. But here's the thing: I'm really low on gems. Under 1k. Even to the point where I now stopped farming IT on weekdays until I'm back up at 2-3k.
14k champ training with t2 stone + leggo book have become the standard. That's worth spending energy on. Then there's all the special events that pop up lately between fusions. Those can be really high value. And I just joined a T6 clan that demands I run a bunch of spider 10h every 2 weeks. There also were the two DDs with lots of oil, that was a massive energy drain. Honestly I don't know how you guys do it. I have a very very hard time keeping my net gem flow above 0 unless I buy daily gem pack.
About this DD being "triple dipping":
I can either run dragon 10h, or dragon 25 with food. The value of the latter has dropped a lot now that even 6* epic gear is sold without rolling. I have to discount the gear almost entirely. Also, I'm at 8k champ training (all in 12-3, no brews) and only 1400 DD points. Even if I maxed out dragon tourney, I'd still be about 2k energy short of the leggo book. So I stick to my initial statement that it's just bad value.
Btw, I just watched a video by Eharbad today where he complains about the state of the game and the massive stat inflation. For me this hasn't been a bad thing, as it's allowing me to catch up really fast to older accounts that spent years farming stage 25. But in that process I have radically shifted my valuation of gear. With blessings and oils, dungeons aren't even that key to high stats anymore. Which is why I try to only run 10h (and 4h FK sigh). Anything below 6* leggo is questionable these days.
Tell your clan leader to f off. Only need to bang spider once a month during PR, and limited gems if any. Tag and forge are the key. Much better gem value in tag, at least for me :)
But yes, as f2p you can't do every good value. And at your level, progression is much more all encompassing of gear, masteries, new champs. Haven't seen the video, but yes the game has shifted from nothing to do (long ago) to easier to progress fast (with spending of course). The easy to play as f2p mantra echoing throughout is only if you've been playing 3+ years and learned to play the resource long game. And this ability wanes over time.
The f2p veterans always were in a 2nd tier behind whales, now in a 3rd tier behind the new spenders... and this will inevitably continue.
Progress is simply a function of time and $$$. Both can be optimized with efficiency, but time is constrained equally, while spend is not. The exact formula was on page 2 of the June mailer.