I think the retal could be lowered, but shouldn't be completely removed.
The reasoning: I do agree with points made by willymychillybily, webvictom, atsanjose, and a couple of others, and I do agree with points made by Cheese, Silence, DaX, Wouter and a few others.
There should be more of a risk of adren rushing top players, the risk being a retal, but if you remove that entirely (rank 1 can retal the lowest rank), I think that would be mad. I am looking at the lowest score possible because it can happen. It may or may not happen either way it goes, someone adren rushing, or the person being adren rushed retaling.
On the other hand: I don't think it's fair that top players can completely kill lower ranked players because of an adren rush. Simply because the higher ranked player (who usually has over 15k land a round) can get his/her troops back faster than someone who has 200 land - the one with the lower land's time is exponentially greater than the person with 15k+ land.
For Ex: I would send 1m harriers to a higher ranked player. I may kill some of his troops, but not much if I do. If he retal's me and I'm (let's say 2%) 2% of him/her, he/she could kill all my troops + those 1m harriers.
From that example, for the higher ranked player to gain back those (I'll say 1m, although it isn't realistic, unless they were INN) 1m troops that were killed would probably be as simple as waiting a couple of bush days to plant, then buy his/her troops up while I would sit there and wait for weeks to gain my staff back and not even at full force.
I agree that it would prove a lesson, but I think that's taking it too extreme.
Just my opinions and justifications - I don't really mind what happens with it.