Compare to the alternative, yes.
First of all your arguments:
1445% with Cleave - That’s WITH Cleave, meaning without Cleave they’re even worse off than that, and any alternative that includes Barb1 would have Slash skills anyway they would also gains from Cleave, so the bonus from Cleave being used as some argument seem pointless.
Redel Crown - You mean Zucken? Zornhau already applies Shock, and the increases is only 25% last I heard so it’s not as impressive as Crown-Mouli or Cross-Liner.
Deeds at 10/10 - adds 10% additional damage and can be up 100% of the time. It’s not bad but the problem is you’re giving up something else to get this by taking Dop 2.
Let’s say in your Shinobi build, instead of what you have, you take SW3-HL2-Barb1-Dop1-Shin.
You get Double Slash (wouldn’t bother with Pommel Blast) that can be cloned, this alone can easily output more than the full 3 skills from Doppel C2 alone.
Here’s math
-Let’s say your Doppel c2 build have 5/5 in all 3 skills and 10/10 Deed (dropped DPE or something)
Zucken 5 - 274 * 4 * 1.25 (shock bonus)
Zornhau 5 - 975
Redel 5 - 289*5
total = 3790%
SW 3 Double Slash with clones
30423 = 1824% (this is without cleave, mind you)
*6 (yourself + 5 clones) = 10944%
And what you get from Dop 3:
Punish attribute (the real best AoE you’ll use when facing mobs that can be knocked down)
Zornhau lv 10 + attribute = 1242*4 = 4968%
…oh wait that alone beat all 3 skills combined at lv 5, and Zornhau is also the lowest CD of the 3 C2 skills at 15s.
And both of those alternatives does benefit from Cleave, so the gap they already have would just get even bigger.