Yes, Youtube ads are getting more aggressive. Instead of just 1 ad per interruption (either pre-roll or mid-roll), it's multiple ads in succession. Instead of a few interruptions, it has increased to many interruptions. Unlike you, I don't get the yellow bars in the timeline that show where the ad spots are anymore.

Many Youtubers have made videos about the aggressive ad changes. Here's one example:

https://www.youtube.com/watch?v=F_tkS4dvi8A

I don't know if any new definitive statistics are out but some Youtubers complain that they don't seem to be getting any additional money even though viewers are bombarded with more ads.