I've noticed a worrying and somewhat depressing trend recently towards new content being obviously slanted towards trying to make people spend real money - and not just a little money, either.
Recent example: oil refinery. As with several new buildings, it's not a proper production building so can't be buffed - to make it work faster you have to have multiple buildings. This makes the production of buffs increasingly pointless - and worse, if you want any number of those you have to buy them for ~10K gems each, which is a not-insignificant amount of real money - many times more gems than you can earn in any reasonable time just by playing.
Another example is event rewards. Used to be that by solid gameplay through an event such as Halloween, you could buy pretty much all the rewards in the shop. You had to work for it, which is only fair, or if you weren't prepared to work so hard, you could spend money to get extra.
Now this year, we see that the best bundle in the shop is ONLY for gems. You can't play for it at all. Also, if you wanted all those dark trees and a second one of each to boost the production (because, again, not buff-able) it costs more pumpkins than it's possible to make, and that's without counting any other rewards you might want.
Another event aspect that has become less worthwhile is adventuring. A few years back, triple loot was introduced during events. It applied to a relatively small list which was different each time - and it was fun because it made some adventures which ordinarily aren't that rewarding worth playing - it rejuvenated the game and made events something to look forward to.
Now, we have a big list of nearly every adventure, and the loot is only double not triple. The result is that when it's event time, everyone wants a pile of Arctic Explosions to run, because that brings most loot for the time/troops used. Worse, it's boring and grind-y. We also see a more or less endless string of short events in between the 3 "big" events; viz. Christmas, Easter and Halloween, but again those events are full of new opportunities to spend gems, which, even if you buy exclusively in happy hours, aren't cheap.
All in all, it feels to me that the game is becoming more and more slanted towards making people want to spend money to get ahead and the interest and gameplay is increasingly fading. I get that the game has to make money, because running game servers and employing staff is not free. But you also need PLAYERS and if everyone gets bored or feels that it's becoming a money pit, they will drift away to other things.