I think you misunderstood my point. Skill is, indeed, not the end all be all, but it's a huge factor regardless. The issue is that, as a Berserker, Lu Bu only has his stats, and each one of his stats is inferior to Sunlight Gawain even if the stats were all it did. Let's put his into perspective. Lu Bu's stats probably have the numerical values of 100 strength, 100 durability, 80 agility (sure the + in each scenario are to communicate that his stats are amped to that degree, and not the modifier), 60 in ME, and 60 in luck. Base Gawain is 40 strength (80 in bursts), 40 endurance (80 in bursts), 40 agility, 50 ME, 50 luck. With sunlight, we're dealing with 120 strength (and whatever the modifier does in this scenario), 120 endurance (same as strength), 120 agility, 150 ME, and 150 luck.
Lu Bu has no advantages, and the only stats that he's not massively outperformed in is strength and endurance, and that's only on average, not factoring in bursts. The average difference between Gawain and Lu Bu in these areas is still 2 ranks. If we're downplaying Gawain, we can assume the + on his stats still maintains an additional B-rank level despite the triple stats, so his strength and endurance would be 160 in bursts as opposed to Lu Bu's 100's. With this factored in, Lu Bu isn't just slightly outclassed in every way including skill, he's heavily outclassed.
Since someone brought it up already, I'll expand on it. The Gawain that was facing Karna was night-time Gawain. Despite having better physical stats on average + prana burst flame confirmed in that fight, he was not having an easy time overcoming Gawain without Kavancha and Kundala. This alone makes Lu Bu doing well against Gawain of 3 times this ability laughable. This also serves to debunk the notion that Karna is top-tier martial artist on the level of individuals like Lancelot who could fight for long periods of time against a much stronger Gawain defensively, and Raiko, who scales to Lancelot (same rank of eternal arms mastery), as the skill gap clearly isn't so great between Gawain and Karna, and detestably no more than Siegfried and Karna.
On the extra trio. Although my memory is hazy regarding the first Extra game, I don't recall Nero ever being called weak outside of Hakuno himself being a hard-cap for her abilities, and her kit does not look weak. Tamamno absolutely is noted to be weak. Nameless is basically EMIYA with minor (stats) and major (clairvoyance) imporvements, and all the ups and downs accordingly. Statements against EMIYA come down to his stats making ranged combat preferable. Look at side/material's entry on Archers as a class, and look at how complete material 3 defines servant "strength." The entire premise of EMIYA's abilities are to be conventionally weak, but their application is strong, particularly when sniping. The end result is a strong fighter that's not a top tier, but has received praise from Heracles, Cu, fake Arjuna, and Richard(him being the shakiest). There's far too much out there to suggest that EMIYA isn't good at fighting.
So, all in all, this seems to be an unnecessary downplay of Nero, Nameless, and Gawain by extension.