I have no idea whether this also applies to others here (? probably?) but I've been a Beta tester for a few other games over the years, and the ONLY way in which they operated their Beta Servers was to wipe them every single time any test was started - with the usual reason being in order to create a fresh (and as bug-free as possible) environment for each new piece of content being tested. And not only did
none of those gaming companies allow the purchase of premium currency on their Beta Servers - they actually gave it away, in unlimited amounts, together with whatever [free] in-game currency the game(s) featured, so that Beta players could test both the F2P and Premium-based playstyles without incurring any personal expense. After all, free Beta testers are doing any gaming company a favour, not the other way round, with free
and knowledgeable Beta testers - i.e. long-term players - being the most useful kind of testers around.
Another feature of those other Beta Servers was the copying of advanced characters [in this game's case it would be Cities, of course] from the Live to Beta environment, complete with all their gear - as was the fast and free auto-levelling and/or de-levelling of characters on the Beta Server, as well as the [free] provision of any and all in-game items/abilities the players might want to use with those characters.
This is all done, obviously, in the name of giving Beta players a genuine,
realistic testing ability, at all levels of the game, without the usual time (and/or expense, where premium content is involved) required to level-up characters, which could take many months or even years.
Another Beta testing requirement was signing a Non-Disclosure Agreement, so that the Beta testers could assess ALL of the incoming new content, including the underlying game mechanics (something which Inno jealously guards, for a reason known only to itself), and thus base their testing upon knowledge rather than guesswork. Those Beta tests also featured much direct interaction between the game's developers - themselves - and the players posting comments, analyses, and suggestions on the related Beta Forums (which were also covered by the NDAs).
And finally, no Beta test in which I was involved lasted for less than six months (bearing in mind that minor bug-fixes and/or trivial in-game alterations don't usually even require Beta-testing) - since less time than this doesn't, in most cases, really provide long enough for players to generate credible analyses/critiques of significant proposed new content. NB: 'significant' new content, as I understand it, would be something along the lines of the Tournament changes (from both last year and this year), new Events, or new Chapter releases.
Of course, the 'catch', if you see it as such (and I didn't, personally) was that no characters created on, or copied to, any of those Beta Servers could be transferred or copied back to the Live environment, and nor could anything those characters had acquired in the Beta environment (character levels, items, premium or any other currency - none of it). The characters and everything they 'owned' disappeared when the Beta Servers were wiped.
But then again, those gaming companies obviously had a rather different idea from InnoGames when it comes to what purpose(s) a Beta Server should serve... but still, seeing as Inno
does treat its Beta Server more like an 'early Live Server' than anything else, I agree with
@SoggyShorts - the least they could do, if they're going to allow the purchase of premium currency and the permanent existence of Cities and Fellowships on the Server, including operating competitive rankings systems just as on Live (in effect, putting the Beta Server on a footing largely indistinguishable from Live), would be to offer generous Diamond discounts, and equally generous promotional offers of all kinds (at the very least, the same as those offered on Live Servers), to the Beta players who give their time for free... even if all Inno seem interested in receiving from those players is, indeed, more on the level of bug/text error reports than the more in-depth content analysis/commentary which most gaming houses also normally hope their Beta players will provide.
All that said... being me, I'll probably still write various lengthy analytical posts here, as and when I can think of something to say...!