Not exactly what I said. I think these two were bad, but the idea of plugins was good.
Especially the uncertainty of whether a user has a plugin for the specific kind of content.
One could use different plugins, say, that plugin to show flash videos in mplayer under Unices.
It's worse when everyone uses Chrome or something with modern CSS, HTML5 etc support.
The modularization was good. The idea that executable content can be different depending on plugins and is separated from the browser. I think we need that back.
And in some sense it not being very safe was good too. Everyone knew you can't trust your PC when it's connected to the Interwebs, evil haxxors will pwn you, bad viruses will gangsettle it, everything confidential you had there will turn up for all to see. And one's safety is not the real level of protection, but how it relates to perceived level of protection. That was better back then, people had realistic expectations. Now you still can be owned, even if that's much harder, but people don't understand in which situations the risk is more, in which less, and often have false feeling of safety.
One thing that was definitely better is - those plugins being disabled by default, and there being a gray square on the page with an "allow content" or something button. And the Web being usable in Lynx.
Yes, as a part of userbase I don't want to be on sale, thank you very much. Hence the comment above.