Reading recent discussions on QL's chances to become a popular game made a wretch for a little while.
I'd consider this usual, as there has always been the sorrow of the people longing for the hardcore DM gameplay and not getting it in the way they want it due to QL's lack of features and activity.
There have always been the usual requests for GTV, balance tweaks and other minor changes that don't belong in a discussion about the game's accessibility to the general public.

However, right now, more than ever, there seems to be a vibe of the game being either utterly doomed altogether, or simply in need of marketing and nothing else.

I consider both of these opinions to be short-sighted.

Firstly, the fact that some people are still discussing the game and playing it clearly proves that there's interest for it. Even more so, the many lows and highs in Quake's popularity prove that it's not just a question of gameplay.. For anyone still in doubt, I dare you to look at the difference of popularity of League of Legends and Heroes of Newerth and tell me it's a difference of core gameplay.

The argument of lows and highs in Quake's popularity also proves that marketing can't solve everything. The game should have a convincing ability to retain new players before getting a full-blown marketing campaign. Right now, it clearly does not.

For this reason I'd like to look at some of the more popular games and discuss a core set of features that they seem to rely on. Let's give it a shitty name, like "The cycle of progress", and go with it.

In League of Legends, with a click of a few buttons you can enter a queue that will find you a 5 vs. 5 match. The matchmaking system finds a match for your skill level, and the process for finding a match remains largely the same for the majority of the playerbase.
The first match you play, you already have a few champions to choose from, and you play the same format and the same map that nearly everybody plays.
As you finish games, you get points. If you win, you get more, but you still get some even if you lose. This gives you new runes, champions and spells to unlock, which all give a taste for content you can obtain quicker with some cash. Even if you're not active, you still get a rotating batch of heroes.

In Starcraft II, the process of finding the next match only really involves pressing one button. The matchmaking system seems very decent at keeping you at a 50% winrate as you get better.
As you win games, you get ranking points and advance leagues.
It's also possible to enter a party of two or more people and play 2v2 or 3v3 games just as easily.

You might notice that unlike in quake live, you aren't destined to get raped in every server you enter to. You don't have to enter a server, wait for it to fill up before having everybody ready up with shitty teams, you get a match prepared for you without any of that.
Your progress, unlike in quake live, is easy to measure and feel, and you can be easily set into a trap of clicking "Find a match" even at times you shouldn't, because it's just that easy.
The above games allow you to start the game in the way it's enjoyable to play it. QL simply let's you hop into a server and hope for the best, which usually isn't very good.

I could give a lot of my own examples by how people get turned away by this, but all is already known by anybody reading ESR. QL doesn't offer a way to enjoy the game for new players.

So let's look at what we could do. If we analyze the differences between LoL and SC2, we can conclude that while both are benefiting from this, the former is more fit for such a addictive experience.
Yes, it's easier, more pretty, contains more clicking around and less action.
However, it's also based on teamplay. And it's not retail - this allows it to have extra content that can be unlocked or bought.

Kind of Quake Live, right? So, I'd suggest:
- add a proper, simple matchmaking system for teamplay modes. The matchmaking has to work - no getting trapped in games you don't like or other shenaningans, just a button to find you an enjoyable match
- add a visible ELO ranking system. Perhaps divide it into leagues.
- add an anticheat, there's no argument for ruined games
- give neophytes a taste of the premium content. It might involve a rotation, but there's probably enough of it so as to allow id to give some of it away for activity. Why not both?

This, unlike taking away features new users should have by right (a jab at some of the suggestions), will not alienate the playerbase and allow QL to retain new players. Then, it can benefit from a marketing campaign. And if a marketing campaign is not to be, at least the game will be enjoyed by those who play it.

When some of us have played the game for more than a decade, it's hard to see use in a marketing before the game can retain new players for longer than a month. Even more so, there's no use in adding premium content that even premium players can't play due to inactivity.