Bear with me this is going to be long.
I have over 20 series, but let's just say 20, rounded. Times 5 seasons a series on average, times 5 discs per season. That'll make it 500 discs. I will never bookmark manually 500 discs. For more than 2000 episodes no less. It's not a matter of time and effort it's the mind over matter thing.
I always follow this idea: I wanna enjoy my collection, not die tweaking it every day. So. Rip the episodes (I did that using 6 drives at once). Then you will discover that the overhead of renaming and tagging them is much less than what you thought. Just make a plan in advance. There are tools for mass-renaming that can do this; in many different ways. Get the episodes' names from epguides.com or the likes, put them in a txt file, and there are tools to rename your episodes from that file. At the very far end of mass-renaming there are regular expression (regex) that can do amazing things. You can have in the end file names for episodes that'll tell you everything, even when the episode was originally aired, what's the online average rating, anything, everything. Filenames to tags in MC after that would be a walk in the park. And then you have a zillion of criteria to work with your material.
But I want even more. I want my MC database to store everything there is, that will ever cross my mind, that I will ever need. I want the duration for each ep. (should I chose not to trust MC scanning my files), an entire cast list for each episode, I want a brief description of the plot of each episode, I want trivia, quotes, notes, comments I wanna have everything... I WANT TO DREAM ORANGE WHEN I FLY OVER MARS!!!
And here it comes: even THAT can be automated (well, without me dreaming orange). There is software out there that does that (and exports the info if necessary), which means that it can be done from withing MC too (it's a matter of online info retrieving scripts). Maybe it'll require some work on the programming side from JRiver (regarding expanding the way (meta)data is imported) but that will be work with a definite purpose that can then be used by anybody and everybody, in a consistent way.
As opposed to (in no order): manual work; there is no automation possible; bookmarking it won't be consistent, so it can't be exchanged even if desired -> series are released worldwide, in different zones and discs differ or are even re-released (X-Files) and people would need to be careful as to why isn't apples-to-apples all the time; series are released in different formats (say Stargate was released in volumes of a couple of episodes (first in UK?) and only after as seasons). The amount of variables generated by such a method far exceeds any kind of good return.
But that's just my point of view. Anyways, one thing that I believe we agree on is that collecting TV series still needs some help.