Adnan Ibrahim certainly is popular among some liberal educated Arabs. But he has some massively problematic views diverging from traditional sunni Islam such as saying Isa (pbuh) will not be returning near the end of times and such. He's got the ears, but he's not a relied upon authority when it comes to knowledge.
Also, there's no need to so vehemently defend Yazid. Yazid was not a sahabi, by consensus of scholars. Let's have the courage to call a spade for what it is. He might not have directly ordered the killing, but he created an environment that allowed for it to happen. As a Muslim, Yazid gets the benefit to have his case dealt with in the Highest Court, as a Muslim it also means he can't be singularly cursed, but beyond that there's no need to deny his involvement, or his (indirect) responsibility. Saying anything else is historical dishonesty and delusion. Since history generally does not have the same requirements of authentication as hadith does, then all reports can be considered.
At the same time, shi'as have to realize that hating on and cursing sahaba is just not cool. Sunnis won't stand it, and will never support it. Here we go from matters of history to a matter of aqeedah/creed. As Sunni Muslims, insulting/cursing/hating/abusing the companions is hypocrisy, and can lead to kufr. We love ahl al-bayt, and we love the companions.
The Prophet (pbuh) never cursed anyone by name, when he did though, it was made generally against the idolator oppressors.
Dr. Blankenship lecture on karbala: http://www.lamppostproductions.com/imam-hussain-ra-a-historical-perspective-dr-khalid-yahya-blankinship/
Dr. Umar's, start at 1hr. 28th min mark:http://www.lamppostproductions.com/dr-umar-abdullah-imam-zaid-shakir-and-ustadh-ubaydullah-evans/