Miraak was never said to have any dragons. In fact, in a time when people worshiped them he was said to "devour them". If you were a dragon would you have served him to face danger from both the other dragons and Miraak himself or joined the dragon cult and receive worship and tribute. He only has dragons now because they're endangered and looking for power wherever it lies.
Yup, he's a total wimp, he took down 10 dragons when they assaulted his temple en force. Do you HONESTLY think that he could have taken Alduin down during the height of the dragon cult? Effectively going against all the dragons AND nords in Skyrim? I don't think so.
Have you forgotten he knew how to bend the will of dragons? That was kind of the main point of Miirak, that he was so powerful that even dragons bent to his will. Also, Miirak WAS a dragon cultist. And when I said "help", I didn't mean just from dragons.
Well...He obviously belived that he could take Alduin. Of course I KNEW he wouldn't be able to, mainly because if he could have taken him he would have done it.
Just picture this, Miirak and Alduin are in the same time period. Miirak CLAIMS he could have killed Alduin, but did he? No, he didn't. Instead he uses that stupid excuse "I chose a different path" to cover his panzy ass.
To conclude, I don't know where you were going with the whole "He killed ten dragons" thing. You sir, just contradicted yourself. My whole point was, Miirak was a big panzy who likes to bluff. He claimed he could have killed Alduin, he should've done it if he could have. The reason he didn't is because he couldn't.