King Arthur: Surprisingly aggressive color scheme. I always thought of Arthur as more of a blue/gold shounen protagonist kinda guy, but the red/gold does grow on me. You put those clunky gauntlets and boots to great use here. I generally have a difficult time using them due to their bulkiness and plainness. However, you balance the bulkiness of the limb armor with the large custom crown and the fur lining on the cape. Oh, and for a cool ruffled/ragged texture on furry equipment like the raccoon tail, use a bump mapped pattern like the leather or scale pattern. You also offset the plainness of the limb armor by increasing the detail on the chest and waist armor. Really cool how the pauldrons merge with the golden chains on the chest armor. While I like the bordering effect on the waistcloth, I think the bird insignia weighs down the design by dragging the viewer's attention too much towards the crotch. It's also a bit too close in size to the decoration on the wrestler belt so it looks like two similarly sized objects stack atop one another. I'd replace the bird with some flashy pattern.
Queen Guinevere: Very nice. Exceptionally good technique on this one. I
really like how you tie together the stickers on the arms with the Elysium jewelry. You also like how you layered the breastplate over the dancer's underwear for the extra bling. Great use of the raccoon tail for extra coverage too. Try applying some bump-mapping on this one too. The helmet's looking good. Reminds me of Marvel's Scarlet Witch. Again, the one thing that I can't completely agree with is the emblem on the waistcloth. Just a matter of taste though. Alotta interesting techniques came together on this one for a very unique look. Again, she's a lot more aggressive than I might expect of the Queen, but I'm sure your interpretation of the Arthurian Legend is a lot more violent and epic.
Lancelot: Channeling Artorias I see. The turtle shell looks especially good in the way it merges with the breast plate's scarf. I also like how the scaled chest armor merges with the waist armor. Sure, I've seen the same technique on your elf prince, but the attitude's different here. Very Monster Hunter kinda vibe. I don't like the coloring on the waist cloth though. It's way too different from the rest of the design. I understand you're trying to tie him to the red/gold motif, but he'll look much better if you matched it with the rest of the outfit. I do like that cool wavy effect on the pocket stickers though. No idea how you managed that.
Merlin: Very natural-looking facial hair. The upper body is somewhat lacking in detail though. You could try layering or bump mapping it a bit for fun. Cool stickering with the double dragons on the hat. Too bad they're so difficult too see. I like how you applied a gold border to the pants with a giant zipper sticker.
Your creations are looking top notch. You've mastered SpecEq, stickers, and bump mapping. Now you can use your techniques to try weirder stuff. Come check out the School of Advanced CaS technique sometime:
http://8wayrun.com/threads/school-of-cas-advanced-cas-technique.18282/
You'll recognize most of the techniques there, but it'll help you to organize and take inventory of all your CaS knowledge.