There was a pause while Mahmood had a fielding injury seen to, that took maybe nearly five minutes. The "strategic time out" adds a couple of minutes. The umpire review on the catch another minute, and the team review about the same. I think the other thing that slows it down is the amount of crowd entertainment they're trying to shoehorn in at the changes, two different 'hosts' in the crowd and a DJ playing music, activating the 'match hero' vote on the app, the 20 ball predictor, etc, sometimes it looked like the teams were waiting to crack on if only everyone would just shut the fuck up for a minute. Aside from that, speaking as someone who had to do at least one thing and often more every five balls, it felt pretty manic and unlikely to be able to get significantly quicker. I dunno if this is a problem, I'm not sure the overall game time was the big aim of differentiating from T20, it's more about simplifying the info you need to understand (balls/runs and less jargon) along with being a product the ECB can own and get terrestrial broadcast deals on. And 'cool' garish graphics of course.
Have to say, the family groups I saw in the stadium - the people this is essentially happening for, along with the same groups at home watching TV - seemed to love it all. The Sky broadcast did a lot of focusing on the beery lads last night but the big screen team were able to show the kids all the time so what you saw at home may not have been a completely balanced view of the crowd.