This isn't correct. The multiclass rules for favored classes did not change between 3e and 3.5. They're identical. 3.0 PHB p56 basically matches 3.5 PHB p60.They created favored class rules when before you had to have all your classes that weren’t prestige classes within 1 level of each other or face steeper XP penalties. So waiting until 5th level as a Fighter to take a level of Wizard was a steep XP penalty. Level dipping wasn’t a thing because you couldn’t just take a level or two and call it quits... RAW. So taking 1 level of ranger for 2W fighting was not by the book.
In 3.5 they introduced the favored class by race rules where each race had their own favored class like Gnome was Bard, and you didn’t take any XP penalties for favored class level disparities. a player could designate his favored class if they played a human.
I also recall but could be wrong that they lessened the XP impact of multiclassing but I’ve not looked at a 3.5 book in over a decade.
Some of us are still a bit salty over how soon 3.5 was released and how much it necessitated buying material all over again. And I'm with the people who feel 3.0 has better compatibility with AD&D, not just in mechanics but also in feel. Particularly the feel.
And if 3.0 was so bad as WotC wanted us to believe, why'd they reprint so much stuff early in 3.5? And if the stuff was as compatible as they'd have us believe, then why would they have needed to reprint it anyway?
But overall, it IS a commercially dead edition. This means as a DM, I can take whatever bits of 3.0 and 3.5 I want and use them as I see fit. Since it's unlikely new stuff will be published, I can make it my own without new stuff interfering just as fans of OD&D, 1e, 2e, B/X, BECMI, and RC do.
Yeah, those "small incremental fixes and improvements" are what bothered me most about the 3.5 update. I think it was an element of project creep at best, though I think it probably has more to do with a developing sense of OCDness around D&D's development, probably tied to a particular person's (or set of people) views. If you look at a lot of those incremental changes, a lot involve regularizing durations, areas of effect, named bonuses, etc. It's like a push to improve the "aesthetics" of the rules, their tidiness, possibly with an eye toward more automation/computerization friendliness.I'll pretty much agree with all this.
I think they definitely rushed 3.5 out way early. 3.5 seemed like two things smushed together:
1. Bugfixes to fix problems that emerged when many people were playing it in a way that was very unlike how it was playtested or how 2e was played. . .a powergame mentality of absurdly optimized "builds" and ridiculous nitpicking of wording that I never saw before 3e, and I didn't see much at actual game tables but read a lot about online.
2. Various small incremental fixes and improvements in ways they thought the game could be improved.
I agree that people who like 3.0 (or 3.5/PF1) have plenty of material to play with. However, as far as D&D as a product line/brand goes, it really has diverged in its evolution - a bit more toward some of its earlier iterations. And I hope it stays that way. I think people learned a lot from the 3e branch, I even think they learned a lot from the 4e branch (particularly about how NOT to replicate that particular experience), and have developed a better and more fun gaming experience for D&D, the 400 lb gorilla in the industry and the primary gateway tabletop RPG.D&D 3.x is commercially "dead", in that it's been discontinued for over a decade, but it's still quite viable as a game. I hate it when people here try to talk about how D&D has "evolved past" 3.x or that 3.x was somehow unplayable. . .I certainly remember many years on this website where people certainly didn't say those things. I also like that there's so much raw material out there for 3.x in the OGL. Between 3e, 3.5e, Unearthed Arcana, and d20 Modern (and Urban Arcana and Menace Manual, both of which had a LOT of SRD material released), there's raw material there to make pretty much any game you'd want. I know there's little to no new 3.x 3rd party material being made either, but again, there's enough already released to last lifetimes, and if someone wanted to commercially release new material based on 3.x, then they certainly could.
So after all: 3.0 with maybe a splash of 3.5 would be my preferred system (after 5e).
Do you know where can I find the 3.0 SRD?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.