I don't see a lot of servants actually respecting their masters so don't see why that would make him less impressive, Berserker isn't exactly under his masters control, Gilgamesh finds Tokiomi beneath him, Saber doesn't see eye to eye with Kiritsugu and Caster seems to be the master instead of Ryuunosuke. That just leaves Lancer and Assassin that seem to have respect for their masters in this war and at least Rider stood up for Waver which shows at least some respect as he didn't stand for Kayneth just smack talking him. Besides why do the servants have to respect for their masters? I mean they're former kings and heroes (most of them anyway) so it should be the other way around since in comparison the mages doesn't have a lot to come with other than the fact that this war makes them their servants.
As for Rider being an idiot he kinda reminds me of Shoryu from Twelve Kingdoms, Shoryu acted like an idiot but his moves made sense and ended up favoring him. Acting like an idiot could benefit him instead of being as serious as the other servants since they could end up underestimating him, the results from this episode does benefit him.
Sorry but I don't remember Saber's Excalibur being faster than any attack the fifth Rider could throw at her. Saber using Excalibur and hitting Riders Bellerophon that was rushing towards her doesn't really mean it's faster than Bellerophon, that's more a question of timing. Shiro could probably throw a stone at Bellerophon before it hit him but that wouldn't prove that the stone he throw is faster. There's also the fact that we don't know if the chariot is his only Noble Phantasm.