If they didn't play the same deck over and over and experiment, which I rarely see raynad do, then you don't get bored
I don't think I ever play the same game for more than 4 months. There's really nothing that could stop me from getting bored if I played the same game as much as they have.
As for the constructed meta, I really do believe it's as diverse as you can possibly hope for. If just any deck could make it to top legend for the sake of fun then there would be no skill involved in deck creations.
If you want to have fun and just create crazy decks with the hopes you'll find something that works, you can still do that, you just have to accept that it's usually not going to make you rank 1 legend. But there's still a real chance for something new to work. Tempo mage, oil rogue, and demon-handlock were all pretty recent additions to the meta, and I'm sure there's other decks like that waiting to be discovered..
And most net decks are still fairly customizable. I'm still doing fine at rank 7 with a mech mage deck that removes Clockwork Gnomes and Antonidas for harvest golems and Mimiron to get the more difficult but more fun kill move. Even snuck a Black Knight in there for that extra fu to Druids. It's undeniably worse than a straight netdeck, but not so much that it's unwinnable. Blingtron + Water Elemental combos also work while still keeping the most insane parts of Mech Mage intact.