I liked 4th edition Dungeons & Dragons. It is a great combination of role-playing game with a balanced tactical combat game for experienced players. But it is not a suitable game for a mass market, it is far too complicated for that. The much less balanced, much quicker, much easier 5th edition is far more suitable for mass popularity.
It also helped that the makers of Dungeons & Dragons stopped shooting themselves in the foot with their internet policy. In the early days of the internet, TSR was notorious for going after fans putting D&D-related materials on the internet. It took a change of owner in 1997 to Wizards of the Coast and then Hasbro in 1999 to get the company to realize that fans on the internet are free advertising. With a game that is hard to explain to somebody who has never played it, a Twitch / Youtube video of interesting people like Chris Perkins running a game with Acquisitions Incorporated at PAX might actually be superior advertising to anything else.
The only people somewhat unhappy by the current popularity of D&D are the makers and fans of Pathfinder. Pathfinder had shoved D&D off the throne of top pen & paper roleplaying game for several years during 4th edition, only to be left in the dust by 5th edition. Now they are planning a comeback with Pathfinder second edition, with a playtest starting in August.