Ah, Nasuverse. Your RPG-like mechanics make every combat discussion look like Dungeons and Dragons optimization. It never ceases to amuse me.
[spoiler]
tier 6
-Kung-Fu Teacher, has some cute tricks, but whitout extreme magic backup just doesn't have the numbers to do anything.
tier 5
-Saber (whitout splatbook items), can't really produce her own equipment besides her ancestral relic, needs mages backing her up to do really anything. Her only saving grace is her awesome nukes, but 1/day really doesn't cut it.
tier 4
-Lancer, save or die would be quite nice, if immunity to instant-death effects wasn't so darn common!
-Rider, quite versatile and can pack quite a punch if you catch your oponent by suprise, but somewhat lacking in raw power.
tier 3
-Berseker, extremely tough to take down whitout Archer shenigans and hits back hard too, overall quite balanced!
-Caster, can melee better than Saber, teleport is quite handy, but if you're trying to blast with her you're doing it wrong, even inside your personal domain.
-Assassin, super stealth is so cheesy, and can actually kill stuff in martial combat whitout magic weapons! However that lack of magic weapons also ends up stoping it from raising another tier.
tier 2
-Archer. Tecnically you only have one Noble Phantasm, but then you just pick Replicate Noble Phantasm and go to town by literally drowning your oponent in magic weapons!
-Saber(with splatbook items)-The supplements of Avalon and Caliburn were basically a godsend for this class, bringing it all the way from tier 5 to here, as now she can actualy engage in melee combat and win whitout heavy caster backup. Wait, she needs a caster to unlock those weapons, but still, at least she can melee better than Caster now!
tier 1
-Shirou-After people complaining in the previous edition that this class could only cook and play buffbot, the designers filled it with so many self-buffs that it's just plain sick. You can replicate even more noble phantasms than Archer, melee better than Saber (and can also copy her unique nukes and Avalon, something that even normal Archers can't do), graft yourself with pieces from defeated enemies, plus the infamous cookmancer build to make an harem out of your oponents
[/spoiler]