Grepolis is a strategy war game, and I don´t understand what exactly you want to be testing while factoring out the core elements of the game. The clicking of island quests, the buying, leveling and assigning of heroes, the filling of construction queus? That all works fine, you need not test it.
Most of the problems occur in normal combat situations because that is exactly what cannot be tested properly beforehand. Slietie, of course, has a certain routine in testing; but most of the people stating in their profiles that they are here "only for testing", and don´t want to attack or to be attacked must be aware of the fact that this is a contradiction in itself. Or how do you test a "hero of war" this way?
I must admit that I have become somewhat allergic to those words in profiles. Just for example: I did not touch a smaller player in the first weeks of Sandbox, because he had sent me a heart-melting PN that he was only here for testing and bug-hunting and not able to log in so often because he was in hospital... and some weeks later, after he had grown and prospered, that same guy, now being member of an reasonable alliance, suddenly was attacking and revolting one of our smallest players. And when I reminded him of his own situation some weeks earlier, the answer was somewhat rude. Depends on the angle of view, obviously.
I started late on Warrior World myself, less than one year ago, and it took me all my experience and even some almost sleepless nights defending myself against the already much bigger players of established alliances surrounding me where I had landed. The main problem is the time you have to invest in addition to your regular national game worlds (and your job and private life^^). Those who want to test properly, should be aware of the fact that testing (= playing) in a beta world most certainly is as time-consuming as playing in any other world; and as in any other world, you will not be able to survive without being communicative, joining a decent alliance and taking part in alliance life and team work - because that´s what the game is all about.
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There are many people, however, who do not really want to test or invest so much of their time, but only are curious and want to have a first look on new features before they are implemented on the regular game worlds. It´s that group of players InnoGames should find a solution for, I agree.
For the time being, I would recommend to start on Warrior World - it´s much more relaxed by now than the younger and more vivid Sandbox.