NO, he is NOT an "elite" striker. I'd call him experienced, high-level, but elite is a longshot. I hate to say it, but the Karate talent pool is fairly shallow and lacks a lot of depth compared to the depth and skill ceiling scene in boxing, kickboxing and Muay Thai. Generally, top Karate guys don't often don't make it far in Kickboxing, bar a few names (Hiroki Akimoto is probably the best modern example. Daniel Vargas is great, but didn't dominate against kickboxing's best. Tenshin is super elite, but gave up Karate as a kid). Wonderboy is great but not "elite". I'm a Wonderboy fan in MMA because I always root for the striking specialists, but I acknowledge the fact that he's nowhere near "elite" as far as being a striker goes.
Frankly, Izzy and Pereira just barely make that classification either, but they are the closest we got to it right now (in the UFC). Izzy actually lost to most of the ranked kickboxers he faced. Pereira did beat all of the guys who defeated Izzy, and he won two Glory belts but here's the thing:
1. The divisions both Pereira and Izzy fought in (including the two Glory divisions Pereira won belts in) are some of the most shallow in kickboxing. Basically MW all the way to HW in kickboxing has a limited and fairly shallow talent pool, and compared to the lighter divisions is pretty ass. When you look at kickboxing and Muay Thai at 150lbs and below, suddenly the fighter quality is comparable to boxing's most elite.
2. Glory Kickboxing has gone downhill for years, and most of the heavier talent (guys at 170lbs all the way to heavyweight) is fairly scattered among a few promotions. Winning a Glory belt is great, but isn't as amazing as it was some years ago when they held more of the talent.
The problem is that Joe Rogan and fellow commentators spent YEARS overhyping the striking ability of the UFC roster, when only now we realize how mediocre most "MMA strikers" are when facing real striking specialists who no longer have grappling deficits. So really, UFC set the bar for striking real low for a long ass time, and you realize how all those "world class striker" comments thrown around UFC commentary were just bullshit marketing efforts. Only now we're actually beginning to see something in the realm of "elite striking" in MMA. Outstriking Masvidal, Neal, and Luque is no special accomplishment for a legit striking veteran because those dudes are neither high level nor elite in that skillset.
You wanna see elite strikers, watch boxing, Muay Thai, or One FC's kickboxing (their Muay Thai is really fucking good too). Or wait until Cedric Doumbé can finally fight in the UFC..