It's not harder the slightest to roll back to an older version, no matter how heavy a patch was... If the older version worked fine, you roll back to it, there is no reason it should not work fine again...
You have two options:
1. Roll back a large production patch which changed a large amount of things in order to fix what is broken.
2. Roll back a small production patch which changed a small amount of things in order to fix what is broken.
Which is better?
I still don't see the difference. They could roll back to the first beta versions of eve if they kept them...
The issue is not rolling back to older versions, the issue is to roll back ingame actions on a character sheet / assets / stats. The issue is not a technical one, the issue is a timeframe one. The more time spent with the new version, the more problematic it will be to roll back to an older one...
It's not just timeframe Lyn, there's other practical issues: Firstly if you've patched something, you've changed the executed code, for an MMO that code has been executed in N machines of different configurations so the actual state of the code and data at the point of the rollback is virtually impossible to determine which means god knows what will actually happen in the process of the rollback unless the rollback consists of a clean install: you could have memory left unreturned to the stack, buffer overflow errors, code waiting for a response that will never come any of which could lead to fatal errors.
Second finding whatever forced you to roll back in the first place, I do a certain amount of coding as a hobby and I can tell you any piece of code longer than "Hello World" has bugs in it, if you want to design code for a nuclear plant you need a very special level of testing that tests even completely impossible hardware conditions and software problems that could never occur... just in case they do somehow. In any case actually coding something is the easy part, debugging it so it actually does what you want it to do is another thing entirely, especially if you're dealing with a logic error which a debugger can't detect (i.e. you *think* you've coded it to do X when it reality it will do Y: since the code is technically A-OK the debugger will ignore it and the code will compile fine, it just won't do anything useful) or a swallowed exception. The more you change inbetween code changes the more possibilities you have for the cause of your problem and the more time it takes to *find* the more time it takes to fix and the longer it stays broken.
Uh... It's not a question of coding, it's a question of correct versioning (cf the version number displayed in every game menu). If your code is broken in a certain version, you don't release that version. If you didn't notice a glitch or a broken version, then you release it but will either have to quickly hotfix it or just rollback while fixing is being made on newer versions.
I don't know how CCP works. I grossly know that in my own experience a patch is nothing more than replacing older files by newer files. If you want to rollback, you replace the newest files by the older ones corresponding to the correct version.
Again, if an older version worked and if you roll back to it, it will use the same exact files and will therefore works as well as before.
Are you familiar with versioning and revision control (SVN, Git, etc) ?