Spikes increase in average utility the more switches that are forced with layers down.
Momentum on offense is maximized by forcing trades sequentially from a dominant position without conceding momentum by switching against opposing threats. Sets like End Pert on offense, therefore, are preferable to Protect or Focus Punch Pert who are walled by common Pert checks, ceding significant momentum.
There are some mons that prey on the passivity of common defensive threats, but few offense mons enjoy switching into defensive threats with status moves, particular under Sand with Spikes down.
I consider mixed offense to exclusively be those team styles that rely on bulky offensive pieces that aim to rely on natural bulk to abuse passivity and wear down an opponent with hit and run tactics. I think those teams have been largely phased out, replaced by Spikes-based versions of the same archetypes or more balanced/bulkier takes with tools like Wish and Spin. Cune has replaced Off Pert, and those styles tend to have a long-term game plan of funneling to Cune or finding a moment to break through with Lax.
It is logical, as you said -- as I was attempting to illustrate -- to use Spikes to overcome the limitations of mixed (pivoting) offenses whose game plans rely on high damage-output without trading.
I see the problem as two-fold.
First: These Cune teams struggle to solve the (Skarm)Gar problem. I think the use of SpD Cune has largely solved BKC's criticisms of Lax teams being Molt-weak, and I think these teams should be solid vs Mix Mence. I'm looking at Light Screen Rest Zap (and other screeners) on these comps and making use of the defensive momentum these teams generate to reclaim some space for maneuvering now that Zap can't revenge set-up common partners, but the common problems with Cune are that you need to deal with Spikes, Sand, and Gengar, and the partners that absorb Wisp concede momentum in a way that is difficult to reverse, bar Guts Fighters.
You could bring Pursuit support, but bringing your own Sand in Tar (or something defensively useless in Doom, offensively in Umbreon) is a hefty tax to pay for Cune and Lax. Guts fighters are Dug-bait and unreliable for bulkier teams defensively -- Salac Hera can anchor but that better suits the tempo of momentum teams, no? At what point is it better to abandon offense in favor of Blissey-based approaches, and is the difference only preferring Lax's mu-spread to Bliss's into a scout? Being weak to the strongest offensive Spikes approach as one of the best options for positional offense isn't a great indicator for the health of offense.
The second issue is that Dugtrio traps mons like Wish Jira, Raikou (potential WoW absorber, with Rest!!), DD Tar, etc. who could thrive on these teams and offer serious compensation, but the problem is more salient with more momentum based approaches. End Pert, CM Jirachi, Tar (still), fighters, etc. all hate Dug, which serves to patch very passive teams that sacrifice pressure and speed in every non-Dug slot, foregoing a balanced approach. I think you can solve one of these problems. I feel that Gar's presence is healthier than Dug's, but the pincer effect of culling so many options is suffocating.
I don't need to further expand, since I've made my points elsewhere, but I think the polarization between extremely slow teams and very fast ones and centralization around Spikes means that ADV's middle class loses out. I'm not saying I want to see a MagDol ressurgence. I'd rather that the Pokemon of the tier are allowed to shine a bit more without being held back by the most extreme and unbalanced Spikes approaches.
To conclude, I'd like to address people who ask why we don't ban Skarm or any other mons that are more centralizing than Dug. Doesn't seem genuine, but in short: there's always some amount of centralization that is necessary for a healthy tier, and I'd rather nerf those centralizing forces by taking away game-breaking synergies rather than chucking the baby out with the bath water. In any case, I think the mons that would be good in a Spikeless ADV (not Skarmless, but Spikeless) should be usable in ADV with Spikes, and the mons that are only good because of Spikes streamline building and reduce the expression in the builder in a way that is anticompetitive in my mind.
People complain about non-mainers who never tap in, beg for pokepastes, and end up farming or winning with less technical play because they're in the right jerk, getting the right prep, or picking up samples. I think the anti-Samples argument is ridiculous because more resources allow for growing the community. I think the emphasis should be placed on how large the advantage a player can get in the builder on match-up, and I think that Dug teams create very imbalanced mu-spreads. So you're choosing between playing a narrow band of honest teams that allow play into the meta at large at the cost of real diversity or using somewhat worse options that bleed value against the best-built teams.
In short, I think players should be rewarded for creativity and exploration in the builder -- able to get an edge that scales with technical ability -- but the tools shouldn't be so busted but imbalanced that the game comes down to RPS checking to see if you are overprepared for the gatekeepers and leaving openings for flawed jank or vice versa.
