It would be a dumb argument for Catalunya which was in September back then, but it‘s still a bit weird that these races are even in these calendar spots.
Catalunya moved to May/June after the Vuelta switch from April to September, but as we moved into the 2000s, it was seeing dwindling fields, especially post-Puerto with the deaths of many strong Spanish teams at the second tier, and falling into the same trap that Romandie fell into at the time, due to a lot of the big name contenders of the time also being Ardennes contenders (Valverde, Sánchez, di Luca, Purito, Evans, Cunego, Schleck brothers) so if they weren't doing the Giro they were usually taking that period of the calendar off. The move to the end of March came in around 2010 if I remember rightly, to try to take advantage of a nice Spanish pre-Ardennes mini-season, connecting the early-season races like Andalucía and Murcia (at that point still a stage race) to Itzulia and Castilla y León as pre-Ardennes warmups. Castilla y León at the time was still drawing some pretty strong fields (see that year's edition with Contador, Soler, Antón and Mosquera battling in the mountains) and it gave the race an injection of interest, but at the expense of putting it at the mercy of the weather.
It's also why we've seen a lot of editions that stick to low and medium mountains and coastal areas, and they've generally had more luck with mountain stages at major ski resorts where the roads are kept clearer (La Molina, the Andorra resorts) or lower altitude ones in the south of the province (Mont Carò / Lo Port most notably), and they do tend to stick to fairly major areas that are likely to be able to be kept in good condition, which has limited innovation - that is improving in recent years and in all honesty this is the best route for the race I can remember seeing, but it comes at the price of potentially being affected by the weather.
At least here there should be enough by way of decisive racing that it won't be like that ridiculous edition where the only MTF got annulled, a break got given rope on stage 1 and then the péloton came in together the whole rest of the way with GC positions settled on countback and seeing stage racers sprinting (and just to add insult to injury, Michael Albasini won) to move up and down the GC...