RACIAL SUIT LINES - by J-Lewis
Pros: Clear lines of progression. Paths of least resistance. Lights and Mediums are cheap(er). Encouraged diversification. Breeds more adaptive players. Compatible with current "no multiple prerequisites" policy. Easy to understand.
Cons: Heavies are going to feel nerfed (should be solved through suit balancing).
Note: I feel this tree is strong for DUST; it's both easy to implement and adds many of the good feelings of progress and contributed effort that this tree needs. Its only real weakness is certain classes being less powerful than the tree would alude, but that's a balance problem.

TECH LINES - by J-Lewis
Pros: Only adds one skill per weapon. Clear structure. Paths of least resistance. Encouraged diversification. Breeds more adaptive players. Compatible with current "no multiple prerequisites" policy. Easy to understand. No SP sinks.
Cons: The list of proficiencies could get rather long, though nowhere near as bad as currently.
Note: Categorizes weapons by technology, and groups all the upgrade skills into a Weapon Upgrades branch. Reduces the need for militia versions of weapons significantly. Added a few non existing skills in the Weapon Upgrades branch (up for debate). There is some potential for the Weapon Upgrade branch skills to play into a modular weapon system...

I tend to agree that yes: nailing core FPS mechanics is really more important right now than the skill tree. But I'm also trying to be forward thinking. The hot topic of the day changes on a dime, and because of that we rarely see threads grow and become longer term topics of discussion, if they're not simple bursts of outrage. This is not one of those threads.
When CCP realizes that the skill tree is the next thing on the workbench to fix, and communicates as such, I hope people flock to this thread to add to the discussion.

Until that point in time I'll be slowly (but steadily) adding content to the thread, hopefully with a lot of help from the rest of the community - it'd be really boring and obnoxious if I were the only one posting.

If EVE has taught me anything, it's that the best way to convince CCP is with a large common consensus and a lot of respectful posting.

So far... Let's just say I'm impressed.

A bit of constructive criticism if I may...

It's fine to have Rails and Blasters together - just like rockets (flaylock) and guided missiles (swarm launcher) are the same group. Each group has two technologies within it.

Additionally, each race uses two types of weaponry... As you may guess, the missing group is drones.

So to sum it up by groups:

Amarr: Lasers and Drones.

Caldari: Hybrids and Missiles.

Gallente: Hybrids and Drones.

Minmatar: Projectiles and Missiles.

And breaking it into individual technologies:

Amarr: Beam/Scrambler Lasers, many sets of lighter drones.

Caldari: Railguns and Blasters, Guided Missiles and Rockets.

Gallente: Blasters and Railguns, fewer sets of heavier drones.

Minmatar: Autocanons and Artillery, Rockets and Guided Missiles.

The only reason the Hybrid group seems overpopulated is because it's the most completed of them all. Much in the same way as Gallente and Caldari vehicles, the first and most often added weapons in DUST development were Caldari/Gallente, so it's pretty obvious why Hybrids is the most populated group.

How do you progress from row 3 to row 4? Does the Scrambler Rifle unlock the Laser Rifle? Seems confusing.
In particular, this is what stops me from being able to make a fully fleshed out tree to put into the OP.

I'm also interested in why you think the tree was one layer too deep.

I think that's about all though.

This weekend's updates:
VL'S MODIFIED TECH LINES - by Vulcanus Lightbringer
Pros: Only adds one skill per weapon. Paths of least resistance. Encouraged diversification. Breeds more adaptive players. Compatible with current "no multiple prerequisites" policy. No SP sinks. Good sense of progression.
Cons: The tree becomes more complicated the more weapons are added. Only really an option once we have more weapons to flesh out the branches (feels very incomplete currently).
Notes: See posts 46 through 50 on page 3.

Yes, that would certainly be a more conservative approach.
However, as I pointed out in the OP, the actual act of restructuring the skill tree is the easy part. One dev can do it in a day or two as long as the change doesn't require a redesign of the interface or system. Because the biggest difficulty is actually assigning a dev, there's no reason not to go all out so it doesn't have to be revisited (hopefully for a long time).

It's how it gets deployed that's the tricky part, because it will require some degree of SP respec, even if it's just for individual skills that get moved/removed. That requires design meetings, and without an Executive Producer it probably won't happen.
Oh, and of course, there's the little fact that this topic hasn't garnered a lot of constant community pressure.

But who knows, I might get surprised one morning.

The best we can do is spread the word. Get people aware of the issue. Get people talking about the issue.

How has this not gotten a dev post?
Atleast then saying they've saw and may or may not implement ideas?
Not insulting devs just curious

If CCP Wolfman's vehicle thread is anything to go by, they might be back on track - he mentions revamping the vehicle skills entirely (both structure and bonuses and stats). I just hope they do the same for infantry eventually.

Here's to hoping he removes tiers at the same time.

New Idea: How about we create 2 different structures, both essentially the same but uses different ideas, using 6 idealistic palette's, 2 infantry, 2 vehicles, and 2 skills, basically what we do is we put some ideas into column A, and 2nd really good idea in column B, when we have enough ideas to fill both structures (One infantry, vehicle, and skill for each) we review, revise and tweak the BEST Structure!

To be honest, the new suit bonuses look a million times better than what we used to* have (at least to me).
It's not so much the actual bonuses, but rather that they are consistent across races.

On the downside, the addition of racial suits and the Magsec SMG and Bolt Pistol will add another 10 million SP to the weaponry tree alone.

I don't think the skill tree will be tweaked at the same time as these items are added, unfortunately.

*read: currently

The links to the redesigns don't seem to work.
I tried the first two in the second post.