why defenders cant go for global top 10 ?

Hello Guys this is Alys Lst & Unfai,

I am playing since game introduced in India almost done 11 months, and i am so glad playing with defender sadly i am reaching every season 3800+ infamy but unable to reach nightmare ok about night mare reaching is not an issue and its my personal. But i have lot of doubts about defender ships they are:

1. But why any kind of defenders in battle bay didn't go for global wide top ranking?
2. And why only Yellow ships are in top 10?
3. Is there any defender can playing vs yellow ship's shield along with tesla bolt if played how was the feeling?
4. And is there any future plans for especially for defender?
5. Is any one satisfaction while playing with defender?
6. And why defender cant reach as easily night mare like other ships?
7. After upgrade the shield time has been increased is the really need?

And Finally the match making system its every one already knows about this issue, now a days the match making system is so horrible i didn't understand why one team had 3 type of yellow ships and why another team didn't had even a single yellow ship same like fixers too ....
There is almost the game had nearly 4-5 updates but still the match making is horrible i don't think so is this issue if every one agreed or not but its true.
And i am uploaded an video the effect of shield along with tesla bolt just see once here the link below.

Thanking you.