More or less, if you aren't using Xyz Summoning to some degree, you aren't winning.
While nothing foreseeable's going to take power away from Xyz Monsters directly, there are a lot of Synchro Monsters coming to the TCG that look to put Synchro Summoning back on the map. Fire Fists, Mermails, Geargia, Bujin and the other competitive frontrunners right now aren't really set up to Synchro Summon, but with Primal Origin coming out in May and a new format developing, strategies that can Synchro Summoncould easily become popular.
A few of those new Synchros came out in Premium Gold last week, the most interesting of which was Beelze of the Diabolic Dragons.Court Of A Beelze
One of the only distinct advantages that Synchro Monsters have over Xyz is the lack of Material fueling their abilities, meaning most of their effects don't run out of steam. Xyz are good for two or three shots in most cases; then you're out of ammo and they turn into beaters. Synchros have no such caveat. As long as they're still around and not being negated, they're generally good to go. Even so, needing to have a Tuner involved is usually enough to dissuade duelists from bothering with them. Beelze and this new swarm of Synchros might be enough to change that, though.
The most obvious threat from Beelze is that it can't be destroyed by battle or card effects, by you or your opponent. Mirror Force, Bottomless Trap Hole, Torrential Tribute, Dark Hole, and all those other tricks don't mean a thing to it. Parts of that effect aren't new or different, but Beelze is the only one with it all wrapped together without a severe drawback. Number 49: Fortune Tune and Wind-Up Zenmaines both come to mind as similar walls in the Extra Deck where Beelze has to compete for space; the difference is a commanding 3000 ATK to annihilate anything inconvenient on the field. Also unlike those two: if something with more ATK than Beelze does come around, it doesn't matter. You can just ram heads with it, take a Little Damage and ramp up your ATK to force-stop those shenanigans.
That effect can be easy to overlook, since there isn't much with 3050+ ATK running around, but it effectively translates to "Bujin can get out of my house." Bujingi Crane's the most direct and consistent answer a Bujin duelist has against anything with more ATK then Bujin Yamato or their Xyz, but dropping Crane against Beelze only bulks it up for the next Battle Phase when it reminds you how upset it is you did that. You can't shoot it off the field with Bujingi Quilin either, because of the destruction resistance. Without battle tricks or destruction, Bujin have a cumulative total of absolutely nothing to fight Beelze with, outside of negating its effect first. Even then, the Royal Decree variants don't have Fiendish Chain, or any destruction effects to couple with Effect Veiler. For some, Colossal Fighter was a pretty good check to Bujin, but Beelze is everything that Colossal Fighter wanted to be when it was growing up, amplified a million times into a two-headed death machine.
If it's your goal to put Beelze onto the field and ride it to victory, you'll want to work toward a 'king of the hill' style of play. Unlike other decks with a similar goal, you get the luxury of Dark Hole and Torrential. Since you can't destroy your Beelze, both cards are completely stress-free, becoming Raigeki with different Spell Speeds. Any time it looks like Number 101: Silent Honor ARK might come around, you can pop up Torrential to put those ideas to rest. Fiendish Chain can save you from Honor ARK the same way, but one Mystical Space Typhoon and you'll be in a bad situation. That's not the case with Torrential Tribute unless your opponent's firing it off blindly, which they probably shouldn't be.
Cutting out the middleman, you can protect Beelze directly with Safe Zone and shrug off anything that might potentially target it to take it off the field without destroying it. Honor ARK is Beelze's worst nightmare, so stopping it's always in your best interest. With Safe Zone, Honor ARK can't even touch Beelze, and you don't have to worry about Mystical Space Typhoon; Beelze won't die even if Safe Zone gets blown up.
Not that there aren't plenty of ways to keep Beelze a source of frustration for your opponent even after it somehow gets taken off the field. When it does finally go down, Call Of The Haunted can slap it right back into action no worse for wear. Thanks to Beelze's built-in durability, Call might as well be a Monster Reborn.Beelze on Wheels
Then there's Plaguespreader Zombie, always ready to roll out from the graveyard even if it does come at the cost of a card from your hand. But if you're putting something like Destiny Hero - Malicious back onto your deck, it's not such a bad trade, making dead cards live. Then you could use a Malicious from your graveyard to Special Summon the one you added to your deck, and get a one-card Beelze onto the field. You'd have to build around that play to do anything with it consistently, but Beelze is so stupidly strong that it's not something to write off. It handles the Bujin matchup almost single-handedly, and both Geargia and Mermails have few answers to it. Short of negating its effect and then using flat destruction they have virtually nothing, and that's where your Safe Zones, Mystical Space Typhoons and general recursion come into play. You can only slay something that's practically invincible so many times before you just can't anymore, and Beelze is the embodiment of that ideal.
Infernities took a big hit losing two Infernity Barrier, but Beelze could potentially answer that situation. Both Infernity Beetle and Infernity Avenger can get Beelze onto the field, even if you do have to -2 for it. That might sound costly, but you're trying to use up your hand anyway and +1 like crazy. With one-card combos that lead into an on-field Beelze, Barrier, Infernity Break and Infernity Doom Dragon, what can you even do?Head Over Beelze
Requiring a Dark Tuner's a little restrictive, but both Krebons and Plaguespreader have the utility to splash into a few different strategies. With Cyber Dragon taking off on a local and Regional level, Blackwing - Gale the Whirlwind could give that deck a way to throw Beelze's power around, too. Raccoons might surprise people with Junk Synchron, and there are a ton of other ways to play Beelze that I probably haven't thought of.
If you have a different deck that you'd use it in, I'm definitely interested to know what it is. Everyone should be mindful to keep this one on their radar, because there's a good chance it'll be a big deal this format.