IdeaStorm can help take your idea and turn it into reality.

The thing with Lightning Bolt is that it takes away from the portability. Who wants to carry extra hubs? I sure don't.
The technology is also far from mature enough. If it turns out to be a good solution later on, it might be a good thing to implement in DELL products, but as of yet, it isn't good enough. That being said, Thunderbolt is not a superior standard at all, it just provides the best speeds.

With time, I think Lightning Bolt has a chance of becoming the best standard as it is based on the most common port: the USB. A lower production- and implementation cost is also something one shouldn't underestimate.

Therefore, it would be wise to keep an eye on the Lightning Bolt technology and its development.

Hi danielps! Thank you for posting and showing your interest! :)

SCREEN
If DELL does not offer more than 2560x1440 on forthcoming laptops with 15''+, they will be passed by competing brands, who offer higher resolution within the same price range with the same amount of power (compare the ASUS UX31A to the DELL XPS 13). It is not likely that there will come laptops with more than 3840x2160 because the human eye won't be able to see the pixels.  By going for "retina display" early and making it a standard, DELL can reduce the cost. By introducing such a high pixel density, it will affect battery life and require more GPU power, but not as much as you suggest. The MacBook Pro with Retina can handle intensive programs used for video editing without hickups at the native resolution: 2880x1800. Games do not fare well on it, but that has more to do with optimization than anything else. Windows has the upper hand with Direct X and all the features embedded within it. With one solution comes new problems, and DELL would need to address them. A more powerful battery and smart use of nVIDIA Optimus when not doing demanding tasks could bypass this. It's all about refining and tuning to get the last bit of juice out of the machinery.

CPU
Yes, the new model should have a similar i7 as an offering, but for the users who demand more for serious work, an even more powerful CPU could be listed as a choice. DELL is known for offering tailored machines, and this would be a missed opportunity.

GPU
The DELL XPS 15 is designed as a Xtreme Performance System. Extreme performance should be synonumous with the option for a high-end GPU. I have already listed suggestions for improvements that could make the machines cool enough to handle it. I agree wholeheartedly with you when it comes to price/ performance. It's the most important part for customers and will ultimately affect their decision.

CONNECTIVITY
HDMI is not needed because you get a display port to HDMI dongle with the laptop. However, you are right when it comes to Thunderbolt. I forgot about that... So: Thunderbolt port instead of Display port, with a dongle for HDMI connection. Do note that HDMI is not compatible with resolutions above 1080p.

OPTICAL DRIVE
Yes they do, and the format is far from dead. BDXL will most likely live a long life, considering the cheap cost of the discs compared to SSDs and HDDS that you can only have one of in the DELL XPS 15 (in addition to a mSATA drive). When 4K and 8K arrives this year, will you want to carry a 2TB HDD with you for a maximum of 5 - 10 lossless movies? Many care when it comes to picture quality and resolution. If you want thinner designs, you already have the DELL XPS 13 and 14.

SPEAKERS
If DELL provides speakers that are above the competition and stay with that design, they will have another positive feature. It doesn't hurt to have extra features if the cost doesn't become too high. By presenting a new standard, the money used on developing it won't be thrown out the window. XPS 1502x had high-end speakers that received praised from every technology corner.

POWERBRICK
:)

WIRELESS
I agree, but by being early, DELL will receive "free" PR and have another feature to list as unique. It will also be cheaper in the long run to ditch the old standard and just have the new one instead. Use it across all DELL units.

Screen: 
Higher screen resolutions also require more powerful graphics card, adding to cost and decreasing battery life. A 2560x1440 screen would be a suitable step up without major compromises elsewhere.

CPU:
The current i7 provides a good balance between cost, performance and power requirements. The next model should stick with a similar class of CPU.

GPU:
A more powerful GPU will be needed to drive the higher resolution, but this isn't designed as a gaming laptop. Give the highest end GPU as an option for the gamers, but price and power is more important here than raw performance. 

Connectivity:
3x USB 3.0 ports is adequate. HDMI is needed for the same reason older laptops had VGA, because all other equipment had it. However, how many TVs, projectors and home-theater systems have display port? If you want Thunderbolt (which has the functionality of Display Port and PCIe), then remove the Display Port connector.

Optical Drive:
People still use this? Remove the optical drive completely, offer a USB 3.0/Thunderbold external drive if necessary. Removing the internal drive will make the laptop cheaper, lighter, and could lead to better cooling or thinner designs. Laptop users on the move use portable hard drives, wifi and SD cards - not Blu-ray.

Speakers:
Speaker quality is not a top priority. Have something that is suitable, but not extraordinary. While I appreciate the excellent speakers and sub in my Studio XPS 16, I just as often connect to external speakers and headphones when watching movies. The money could be put to better use elsewhere.

Powerbrick:
Of course, smaller is better, and selecting components with low power requirements will make it possible to reduce the size.

Wireless:
The new 802.11ac standard would be nice to have, but not a must have, as the majority of routers will not support it for some time.