Merlin the Tuna said:...You realize that neither of your examples is usable in the slightest without a "PLEASE MAKE THIS WORK" fix of a PrC from a splatbook? It's kind of a shoddy approach to discussing problems with the core multi-classing mechanic given that a 4e Rogue with Arcane Initiate seems to be approximately a bajillion times closer to your character concept than a 3.5 Rogue/Wizard that pokes at people with a flimsy dagger held by his weak girly arms. Seriously, your BAB is typically going to be the same as a Wizard, or potentially worse. (Hooray for Rogue 1/Wizard 1!) Even if you could hit something, your sneak attack stays as unimpressive as your caster level, which puts your damage output at "miserable," improving to "unremarkable" in ideal circumstances. Your HP is going to be halfway between "paper sack" and "wet paper sack."
But at least you've got Trap Sense and Summon Familiar, right?
The characters you describe are catastrophes in the 3E core rulesets. Are they fantastic in the 4e one? Maybe not. But they appear to be workable.
As the "fine" folks on the WoW forums might say.... QFT!
3e multiclassing was beyond broken, it preserved all the power of the core classes that prior versions didn't have and none of the flexibility of them.
Sure you could pick a different class each level. Sure you could take as many different classes as you wanted. But without resorting to prestige classes and splatbooks that came much later in the 3e lifecycle, how many of those combinations really worked worth a wooden nickel in terms of actually being reasonably effective?
I guarantee you nothing that involved arcane spellcasting did, if only because of arcane spell failure while wearing armor. You needed a prestige class and special kinds of armor to work around a limitation that made either your melee levels worthless or your caster levels nearly so.
Even multiclasses involving divine spell casters were more often hosed than not. Saving throws were based on level of spell, and at 20th level a 10/10 multiclass was limited to max level 5 spells; this was the equivilent of enemies getting +4 (9-5=4) to resist your best spells. Because your caster level was maxed out at 10 (without specialized feats) you were at a -10 penalty (20-10=10) to bypass spell resistance. If you were an arcane caster and wanted to cast spells while armored or using a shield you needed the "still spell" feat which meant your 4th level spells were treated as being 5th level for memorization purposes but were still 4th level for purposes of saving throws - your 5th level spells might as well not exist. The additional +1 chance for your enemies to make a save versus your spells added insult to injury.
Fighter/rogue worked ok, multiclasses of X/cleric or X/druid worked decently if you built around the concept of someone who only self-buffed. Any X/paladin multiclass was impossible because once you gave up being a paladin you could never take it up again. Of course the reason fighter/rogue worked was the core rules fighter class was underpowered and you didn't really lose much by not taking levels 11-20 of it.
3e multiclassing rules and "fixing" them sucked up a not-insignificant portion of Unearthed Arcana for a reason, and the explosion of prestige classes as a workaround for the massive brokenness of them. 4e multiclassing may not be great, but please at least be intellectually honest enough to admit that the 3e system was much more of a nightmare.