I am not sure why we are going in circles. But,
Sure, they look alike. BUT, unlike other air crafts "upgrades", the E/F was redesigned - it has some 40% fewer parts than the earlier version and is much, much larger. Seriously, since I am not aware, can we say that of ANY other aircraft? American too? Furthermore, for what it is worth, some wanted to assign a new number to it.As to my remarks about the SH,one cannot deny that the SH is an upgrade of the basic F-17/18,just look at it and the earliest examples.It is NOT a "new" aircraft,no matter how good the upgrades.
Even the MKI is a redesign, looks like the Su-27 (with canards granted), but the MKI is larger than the original plane and was a redesign. It is a totally different plane.
Would the proposed MCA be a dual engined upgrade of the LCA? I think not, but it will have plenty in common with the LCA.
What we can say about the F-18 E/F is that it is no F-35 - a totally different design. BUT, that was the intent for the F-18. To the extent that the USN has a totally diff name for the E/F - so as NOT to confuse it with earlier F-18s - a very deliberate act.