A common statement is that the new enhancement system emphasizes pure builds over multiclass ones. This thread is trying to discuss the impact of the new enhancement system on builds which have ranger splashed, or are splashed rangers.
After some general remarks, I will discuss some existing build archetypes, and list what they gain and lose with the new enhancement system. For now, I am focusing on builds using the tempest PrE. A discussion of AA, DS based builds and builds which splash ranger is going to follow at a later point.
I will call the enhancement system which is currently on the live servers "old". I will not go into deep detail in regards to, e.g., which damage bonuses are changed, but rather indicate if the new enhancement system support the same class "break points".
Toughness. The ranger didn't have access to a Toughness enhancement, so the change to +5 HP at every 5th class level is an overall boon for rangers, with a slight nudge towards pure builds. This particular choice of numbers does not exactly mesh with existing archetypes, as these are currently based around multiples of 6, not 5. A 12/6/2 will lose 5 HP over a pure build. (if the access to HP enhancements is the same) I think this is acceptable.
Tempest-Based builds
The old enhancements did not offer a Melee-friendly capstone, so it was easy to opt for a splash. New enhancements are less feat-demanding, so the new enhancements will allow more flexibility in this department; you don't need to take spring attack and mobility.
With classes associated to trees, a Drow could make a deep splash, and still get the full tempest tree (similar to Elf or HElf AAs under the current system), which is not possible under the current system.
18/1rog/1fgt or monk. Exploiter and Tempest Trapmonkey.
All the tempest enhancements are available except for the final core ability, the Tempest Capstone. The old Tempest III benefit of +5 Doublestrike is still available. Additionally, these build have access to some low-tier rogue/monk/fighter abilites.
Haste Boost is now a tier 2 tempest and probably thief acrobat ability, so one has to decide between Sprint Boost and Haste Boost. So on this split, you cannot have sprint boost and haste boost at the same time. Note that a pure Tempest is facing the same decision. One would have to splash deeper to get both.
15/1rog/4fgt. New-School 'Exploiter'.
A build which gives up Tempest III to make room for some feats, probably Maximize and Quicken, Weapon Focus and Weapon Specialization. The new ranger enhancements not accessible are the tempest capstone and "Whirlwind", the core enhancement which has taken the +5% double strike bonus of tempest III.
1rog will probably not give access to Haste Boost. It's debatable if
Kensei Enhancements: Access to the first 2 core abilities, for a small damage bonus. Access to almost the full Kensei tree, with the exception of the top row.
SD Enhancements: this is where the toughness bonus is hiding. There is only little reason to take this tree.
Overall, I think that this kind of build gained a lot of extra damage via the access to the Kensei tree. Since there is a 3-tree-limit, the benefits of 1rog are getting smaller. Also, getting more HP from splashing fighters is made harder.
12ran/7rog/1mnk. The Prodigy.
Just like the 15/4/1, you don't have access to Tempest III, or it's equivalent core ability. 7 Rogue opens up the whole trees, and 3 core abilities of eg TA. Haste Boost is in the TA tree, but extra SA damage is in the Assassin Tree, so you could take Sprint Boost, Haste Boost and extra SA damage, if you don't take any of the other ranger trees.
I think that this build archetype does not suffer greatly.
12 ran/6pal/2fgt. Tempest Tank.
Similar reasoning as for the prodigy: Access to some paladin core abilities, and the whole paladin trees. If this is viable remains to be seen, and depends on the layout of the paladin trees. Since they are consolidating HotD and KotC into one tree, there is hope that the interesting tanking abilities (eg divine righteousness) can be found in the DoS tree.
Summary
So far, it looks like splashing is still an option for Tempests. There are some changes which make certain choices worse (rogue 1 splash, I am looking at you!), but it does not look like any of the discussed builds is made completely unviable.
Questions
Did I miss an important existing archetype?
Are there aspects I didn't consider here?