It's all about content.

Example:

BO3 has so much content that's worthy of a full price game. And now they're going to release a stand alone MP version for PC for just $15.

Thus...Star Wars Battlefront is not worth full price.

Oh, I know. It's just that it's always brought up as an example and I think it has more to do with the negativity around that game and it's average gameplay rather with its length. So, it's not directed at you. Just a general comment.

What about the consoles? :P

Games should be more expensive than they are now, I'll open with that. With budgets skyrocketing and games actually being cheaper now than pretty much ever before even when you don't talk about inflation, $70 should be the standard now, minimum, if we want finished games. Yeah I may boycott Ubisoft or EA because of their horrible practices but they sort of have an excuse to release unfinished products since the moment they try to raise the price to justify the budget they get slammed.

That all said, the experience is key to the price of a game. A game like Journey shouldn't be $15+ but it is because it provides a unique narrative that nothing else does. A game like Braid might only be three hours long but it's got the wow factor and the depth in the plot to justify the price. A game like The Order is five hours of subpar plot with very little gameplay substance for $60, but a game like Fallout 4 has relatively average gameplay and a subpar plot with an addiction level of 11 forth same price. It's all relative, and that's why we should try to go back to a slightly less regulated market where developers can be reasonable but the consumer has to agree to cooperate if they want to get the experience they desire. The Witness is a good example of this; it's considered indie but John Blow didn't give a damn about indie scale pricing and he priced it correctly. People clearly didn't care too much either! The trouble comes when a big wig tries to take advantage of this concept and consumer trust, at which point it all falls apart again.

I'd base the price on the time it takes to beat the game fairly fast (ignoring all side quests). Basically, 20+ hours would be $60. $50 if you only hit 11-15 hours. $40 for 7-10 hours. $30 6 hours or below. Knock off $10, if the game is 2D. Paid DLC shouldn't exist, ever. If base prices go to $70-$80. And if you buy a LE of a game, for a high amount. All paid DLC no matter how late it's made, is free.

Only under special cases would this be voided. Like making Poken Fighter have all 700+ Pokemon. Or if you have 40 characters that can do attack combinations. A game that does fully destructable enviroments. The first entry in a fighting game. That has 100+ characters. And didn't get to build the roster up, over multiple versions. Things like that. I'd also void these rules if the sequel has less content, than the previous game. Like Sims 4. It didn't equal base content/features of Sims 3. The price is dropped by $10.

Ah but Deadpool is almost an hour shorter than the Revenant.  Should I pay that much more for more content?  Quality of content is important as well as replayability.

That's the thing. I prefer a 7 hours amazin experience, that 100 hours of Meme Run, for example, if it was that long. The problem is the next one, there are games like costs the same, nevertheless, one lacks a lot if we compare to the other in content and quality. But obviously, how do you prize quality? That's hard. The thing is we can't make an algoritm to prize a game containing quality, content, budget, etc. because the prices would be way over-the-top. So in the end each one of us has his own metric for this. The problem is that maybe developers feel like the standard prize (60) is not enough for the budget they have expended, so, that's where the DLC practice comes into play. But is that unfair? I don't know, in the end, we must admit that budgets have skyrocketed and this is what cause DLCs to exist. Maybe one option would be to restrain their budgets and make fully-fledged games at a standard prize without DLCs. 

Why not? The people who build the game, give the Q&A team logs. Then you average out the time. That's how people do it now. You just then make a universal pricing scheme. Like when they give the games rating. For hitting certain things. It acutally help people. The game shows up as 50$. Oh it's 10 hours. I have that time to kill.

If I were a publisher I would price it so I can try to break even or make a profit ...

If I was a gamer I'd let the market determine it's price ...

If it were me personally, I would like to be as cheap as possible ...

There are many facets to your question ...

What the market dictates it's what goes and I agree with that logic for the sake of bussiness.