First of all I need to say how great the academy's temporary location is. It's not convenient for me and the mat layout can best be described as hazardous, but it somehow makes it feel much more awesome that it's above a tyre and rims shop down a side street.
It was my first evening training in a while though and going up against Dieter, who I hadn't rolled with for ages showed me that you need a lot of variety. Because he smashed me in a variety of ways. There is a saying in chess of "you can only get better by playing people who are better than you". And this is completely true with Brazilian Jiu Jitsu. Whenever I have the opportunity to roll with those who are much more experienced than me I come out of the session feeling like I have learned so much. Having someone highlighting every issue with your game by capitalising on it can be demoralising, but it is also such an important part of learning.
If you only ever rolled with people who couldn't show you what you were doing wrong, the you're never going to make corrections or improvements to your game. But when someone destroys you and subs you once a minute for the duration of your sparring, you realise quickly what mistakes led to that in an effort to avoid the pain again. Then you get the chance to make a whole new set of mistakes, or have existing ones highlighted by another sparring partner.
To be sure it's nasty to be so utterly thrashed by someone, but it's far better to have a glaring issue with your game highlighted in some sparring than in a comp. And at least someone in your club should be willing to take time out after the roll to discuss it with you.