It'll feel like a slower start but the excitement will ramp up towards the later games when you start to see who could progress etc. which will be very different to the old format where half the groups were virtually decided after 3 games. You also get the interest of seeing many more varied matchups, rather than three fixtures played twice for each team.
I don't think the format has much to do with some of the sillier scorelines that have happened, the teams on the receiving ends aren't exactly all newcomers - Young Boys, Zagreb, Celtic.... Slovan Bratislava being the only particular exception so far as they've only reached qualifying rounds the last 4 or 5 seasons. You could just have easily seen Dortmund and Celtic in a group together with a silly scoreline, like when Celtic lost 6-0 to Atletico last year. You could probably put forward an argument that the approach from teams is a bit different now they're not in 4 team group, so they're a bit less cagey and some of the teams see some value in having a decent goal difference but i'm not sure it's really having that significant an effect.
I don't think the format has much to do with some of the sillier scorelines that have happened, the teams on the receiving ends aren't exactly all newcomers - Young Boys, Zagreb, Celtic.... Slovan Bratislava being the only particular exception so far as they've only reached qualifying rounds the last 4 or 5 seasons. You could just have easily seen Dortmund and Celtic in a group together with a silly scoreline, like when Celtic lost 6-0 to Atletico last year. You could probably put forward an argument that the approach from teams is a bit different now they're not in 4 team group, so they're a bit less cagey and some of the teams see some value in having a decent goal difference but i'm not sure it's really having that significant an effect.