Does anyone happen to know if there's any way in Kodi to just browse folders on my share drives on my computers or on a hard drive without having to "add folder"?
There are basically three ways to use Kodi:
1. Most limited way where you just navigate to the file in a folder directory and play it. Unless the content is local (aka on THAT machine) you have to add that folder as a source but just the first time, it will remember it. Then you can even favorite that source to make it easy to get to from the home screen. This is the most basic way of using Kodi, like you would use VLC or any stand-alone media player. I play my 4K content this way, as my 4k library is so small I don't want it polluting my larger library (aka way #2).
2. Add in folders, with properly named media or correct nfo files, as sources to a larger library. In this mode Kodi scrapes the content info from either the nfo file or a website like thetvdb.com and then loads all of your similiar sources (say all the movie sources, or all the TV sources) into one single library. Once the library is built not only do you get things like cover art, fan art, and descriptions, but you also get to use the "TV Shows" or "Movies" part of the main menu that you might have seen. Once the library is built ALL your content is easily sorted by year, actor, genre, etc. Add in a MySQL setup and this library can be shared with multiple Kodi installations for a seamless whole house experience. This is the "primary" way to use Kodi.
3. Use external content sources. For example you can load all your content into a DLNA server and point Kodi to that server for a library effect without Kodi building that library. Or you can use the video plugins to stream content from other websites. Or you can tie Kodi to a PVR backend (or just a HDHomerun directly) and stream content from that backend. There are more options here I am missing, point is that Kodi isn't used to navigate to content or organize it, it is only used to consume content.
The magic of Boxee was that it took the "hard" option in Kodi (the second option) and tried to automate it some. Rather than you manually adding in folders of PERFECTLY named content according to Kodi's standards to a library, in Boxee you would point it to your media source and it would try to apply its own logic and find a way to automatically put that stuff into a library. There was no real concept of "library mangement" like you do in Mediaportal, or Plex or Kodi as the whole point was Boxee was supposed to figure it out for you. That was Boxee's edge, the reason for forking from XBMC (at first).
Boxee had other benefits (3D subtitle support before anyone, automatically downloading subtitles, etc.) but most of those either have been brought into main Kodi or turned into plug ins. What hasn't been brought into Kodi from Boxee was it's automagic "I will make your library for you!" scraper, and that is because people like me would FLIP OUT. That might be what you are missing.
The Boxee approach didn't allow for media hoarders like me (who are Kodi's biggest users/supporters) to have PERFECTLY managed libraries. I HATED Boxee back in the day because its logic was all over the place as it tried to figure everything out for me. In Kodi if I call something "Star Trek Enterprise S01E01" I know FOR A FACT that Kodi will see that as the first episode of the first season of the correct Star Trek, or if it doesn't at least it won't add something it isn't to my library. With Boxee it was a crap shoot which direction it would go. "First season of Voyager? Sure!" The inexactness is exactly why that Boxee vision of library mangement died with Boxee, hoarders like me don't need hand holding on the library management part.
Boxee was great for the low-end media downloader who had some large folder with tons of straight off the net with names like "Trek.ENT.101.SCENETAG.HD.avi" which Kodi didn't know what to do with. At least Boxee would TRY and guess what show and series that file is, while Kodi will wait around for you to give it the "S01E01" naming convention it prefers. The truth is that this Boxee functionality will NEVER be in Kodi, because now all of the Boxee "magic" is done on the content download side. Without pointing out exact softwares let me say that MOST of the major pieces of pirates software in 2015 not only FIND the episode of Enterprise you want to watch, but after download the software will rename "Trek.ENT.101.SCENETAG.HD.avi" into the convention Kodi wants before it even moves the file to the correct place in the server. Hell the software can even notify Kodi and automatically add the content to the library if you want. Point is, Boxee and its shotgun approach to file scraping is no longer needed. In 2015 the file should be named the right thing BEFORE the Kodi can even see it, and if there was a bad guess on the part of the renamer it happened in a place separate from the library so its easy to clean it up.
The replacement for Boxee IS Kodi PLUS time. The time element is when you either clean up your file names manually in a way Kodi likes (I have probably personally spent over 40 hours in my life just running TV shows through a renamer program for that reason), or you learn software (like Media Center Master) to do that and build a library for you. Or you put together a DLNA setup. Or you just favorite all your sources. Etc. If you just load in your folders and expect Kodi to do the rest like Boxee did you will be disappointed by the results. Kodi doesn't hold your hand like Boxee did.