I find this to be really sad. I loved Martin Lopez's drumming in Opeth. I found it to be very fitting and dynamic. Additionally, he is the original musician found on many of the band's albums and so it was special to see him perform those songs. It won't be the same, but I am glad that the band will continue.
As for Martin Axenrot stepping in as the replacement...I agree that he's a good replacement, but at the same time I really do feel that Lopez's drumming had more of a touch for Opeth. I feel that Axenrot's drumming indeed generally has more of a straight up death-metal approach. Perhaps he will adapt to the band more, though...?
The suggestion that perhaps Axenrot will convince Mikael to return to Bloodbath (especially now that they'll be on similar schedules) seems like something I wish would happen, but it doesn't seem too likely.
I'm also curious about Martin Lopez's new project.