be-ach, exactly my thoughts. Alguersuari may be very talented, but he's 8th in WSR, for God's sake... In WSR which is below GP2, and even in GP2 I don't see a driver who really should be given a race seat this season.
I understand that with this limited testing, Alguersuari will benefit from driving some races before his first full season in 2010 and this will help him a lot next year (if you think about it, there's no other way to gain experience...), but I wouldn't put him in the car in 2010 either. He turned 19 in March, he wouldn't miss anything if he spent one more year in WSR or GP2 or whatever.
On the other hand, STR doesn't really risk anything, his results can't be much worse than Bourdais's (and don't forget, Alguersuari's got Repsol behind him.)