One of the big bugbears I have with Piwik is that you are restricted to looking at data from one time zone.
In practice on most big websites I have, there are several different advertisers. Some are on mountain time for reporting, some on central, some are in the UK, some could be in Europe.
So when I look at my stats which are in UK time, then in reality it is nearly impossible to match up the stats, which greatly lessens the power of Piwik.
This is especially important for Goals.
At the moment I am considering nuking the entire install, because I set up the stats to be in UK time, but my main advertiser is now in Eastern time. It makes all the stats from the 30 goals I set up pretty pointless, because they are about 7 hours different.
I would have thought this would be relatively easy to fix.
Just set up a parameter in the database that sets a time up as zero, and then adds or subtracts based on how many hours ahead or behind a time zone is.
But regardless of the technicalities (and I appreciate this may be more difficult than I realise). I do think this is absolutely essential.
I should be able to log into my install and see the stats and goals from any timezone just via a dropdown, and then for example the company that reports in Eastern time I could look at with it set to Eastern time, the advertiser from the UK in Uk time etc.
And almost instantly, the stats would be 10 times more useful with exactly the same basic data.