not really a xurk believer. first of all, let me explain why i think this mon is bad on offense specifically. speed and (perhaps surprisingly) defensive utility are extremely high-value traits on offense mons, and xurk has neither, resisting nothing and switching into nothing. i've gotten some good use out of mons such as primarina, empoleon, ferrothorn, kingambit, and mega altaria on offense despite their offense stats being a fraction of xurkitree's. the reason for this is that they're much harder to dislodge, matching up well into common progress makers and doing a good job at harassing the regenvests that come in to grab momentum and spin away their hazards. so they can end up clicking attack after attack, while xurkitree only gets to attack once and then has to run away (specs also doesn't help with this).
if i did want to use xurk on offense, the set i'd probably consider first would be take heart/thunder cage/ice beam/sap, leftovers, speed boost. the imposter matchup here is kind of dubious cause they can try to kill you with ice beam, but i can see the extra power and speed being legitimately really good compared to competing th users; you can very realistically get through softer answers like topsy flutter and knocked regenvests. from there i'd probably add on an "anti-th th" like bounce fairyceus or scales groundceus (taking care to prep for blobs) and continue the team as normal. the idea is that by fixing xurk's speed with speed boost and its survivability with th/sap, its strength (special attack) is able to shine through more.
you can also try sun growth speed boost or torch unburden but that works on like any mon in the game, and also xurk struggles cause of low survivability (making it harder to switch in and set up) and inability to ohko imposter from +2. i had this one gen7 team with specs triage xurk, but this (and its np/th triage cousins) are generally pretty silly.
with aggressive elecs, i think you'll get more success out of mirai, pika, ampharos (prank dbond), hands (something like leftovers hazard/2atks/bunker adapt), or sandy shocks. not including eleki here because it unfortunately does not do damage.
anyway, moving on to slower styles like balance. my first thought here was "what does this do over zam, they lose to all the same things except for specifically spdef steels, and zam has speed" then i thought of using both of them together and realized that was actually pretty funny:
Xurkitree @ Choice Specs
Ability: Electric Surge
Tera Type: Electric
EVs: 252 HP / 252 Atk / 252 Def / 252 SpA / 252 SpD / 252 Spe
Modest Nature
- Rising Voltage
- Sandsear Storm / Volt Switch
- Fleur Cannon / Ice Beam
- Knock Off
Alakazam-Mega @ Choice Specs
Ability: Beads of Ruin
Tera Type: Psychic
EVs: 252 HP / 252 Def / 252 SpA / 252 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Psycho Boost
- Moongeist Beam
- Volt Switch
- Fleur Cannon
the synergy here isn't bad, knock xurk will be really effective at drawing in specifically regenvest ting and imposter to get knocked, leaving zam to go crazy as a result. this is a fine core and you can build a fine team around it. unfortunately, knock xurk improofing throws a wrench in our double regenvest + fc + imposter schema, but we can amend this with options such as fleur xurk + fc tidy/shackle groundceus with ogre and registeel as the regenvests.
but also look at this shit. i came up with this in like 5 seconds:
Greninja-Ash (M) @ Choice Specs
Ability: Drizzle
Tera Type: Water
EVs: 252 HP / 252 Def / 252 SpA / 252 Spe
Naive / Rash Nature
IVs: 0 Atk / 0 SpD
- Water Spout
- Steam Eruption
- Volt Switch
- Moonblast [for koraidon/giratina] / Fleur Cannon / something else, idk
Sandy Shocks @ Life Orb
Ability: Sheer Force
Tera Type: Electric
EVs: 252 HP / 252 Atk / 252 Def / 252 SpA / 252 SpD / 252 Spe
Modest Nature
- Sandsear Storm
- Thunder / Wildbolt Storm [more reliable vs desolate land hooh]
- Steam Eruption
- Knock Off
how 2 use: step 1) lead gren vs imp, step 2) hard shocks on volt switch and bluff water absorb
anyway, specs gren can be really finicky at the best of times, but at a glance this core looks a lot more fluid to use than the one above. we aren't wholly reliant on choice item predictions to do anything at all, opposing imposter is on a much shorter timer, shocks unambiguously ohkos itemless ting in rain, just in general the number of mons that can expect to survive vs this is pretty small. gren counter + defensive flutter can maybe do it, blissey can do it, weird scales like zac can do it. who cares. throw on fist plate gag steelceus 3rd (to block split), run like giratina + fc zac + regenvest guy/imp or some shit, watch the wins cascade into your palm. (edit: i got a ladder game
here, gren/shocks/steelceus just tear apart the overly passive core)
i would say that the takeaway from all of this is that 1) extremely one-dimensional sets can be strong, but i don't think they're ever the best options available and they're nearly always contingent on matchups and/or choice predictions, and 2) xurkitree doesn't really lend itself to any other type of set. so i would rather see other unranked mons get a spot before it.