It's probably because, unlike Misaki's, Ritsu's indecisiveness actually has a reason in that he nursed a heartbreak, even if it was all due to a stupid misunderstanding.
And probably also because, unlike Ritsu, Misaki is dating with the person he loves since now 4 years. I can't understand why he is so shy and indecisive since he is dating Usagi quite a long time (4 years !!!)
Sorry if my english is bad but I am French so I hope you'll excuse me for my mistakes.
Weird. Both Ritsu (Hatsukoi) and Misaki (Junjou) are similar in that they are indecisive and rarely admit that they like their partner. At times, they both end up hurting Takano and Usagi but I find that I feel more frustrated with Misaki than Ritsu.