have you made this IPA before with another strain?
the reason I ask is that while I love Amarillos, I really don't like them as a single IPA for the fact that their bitterness and flavor come across as 'soft'. they work well taming down some of the more aggresive ones, and are wonderful as aroma hops, but they can't seem to give you that enamel scraping hop goodness like some of the others. I made an all Amarillo IPA once and had similar comments to yours. JMO.
I made a similar IPA recipe with all-summit and S-04 just before I made the Amarillo IPA. Of course there were fewer hops in the Summit one (because of the higher AA percentage). And I used English malt in the Amarillo IPA (Crisp MO and Simpson's Medium Crystal), and American malt in the Summit IPA (Briess Pale and Briess 60L). The beers were the same SRM, IBU (on paper), OG and FG. I mashed both at 150. There were 4 oz hops in the Summit IPA and 6 oz in the Amarillo IPA.
It is possible that what you say about Amarillo is true, that they are a "character actor" in the hop world (I have had great experience using Amarillo with Centennial). But what is really lacking in my beer isn't "bitterness" or "harshness" but hop flavor and aroma. It's all there, just hidden under a deeper malt character than expected. I will have to try another IPA with 1450... I have no shortage of Cascade, Summit, Simcoe, Willamette, or Nelson Sauvin at the moment... Maybe a Summit/Cascade/Simcoe IPA?