We have to remember that the Barcelona track is quite a bit faster during the winter testing months than what it will be come race day. Last year Kimi was fastest time in Testing a 1:22:7 In Quali he managed the fastest Ferrari time of 1:23:1 this after 4 months of development.
I do however expect them to at least match the times they do now in Quali due to the much more extreme development curve i expect they will have this year due to the new rules.
It is better that we compare this years testing times with last years testing when looking at how much cars have improved as the track conditions are so much different later in the year. right now the times are bang on 3 seconds faster than last years Testing times. I expect that before the end of day 4 someone will pull a 1:18:5 out of the bag a glory run on ultrasofts (if they can last a lap)
With ham doing a 1:20.4 and then doing 15 more laps after this I do think that fitted with SS and a close to empty tank of fuel and that engine in Quali mode he could if Merc allowed him break in to the 1:17s. But thats not mercs way.
I as a Hamilton fan was concerned at the beginning of testing that Merc were easily going to run away with things again. But Hamiltons comments today about Deg and lack of grip give me some hope that Mercedes are not as superior as i first thought and others may be allot closer to them than i expected and we might, just might get some racing this year at the front of the pack. But then again a 1:20.4 on soft tyres with a minimum of 16 laps of fuel on board maybe gives some idea of what his and Mercedes expectations are, when he is unhappy with that time and this was done whilst he had no grip