Panning the screen is a love-hate thing for some users because the SW has to decide on whether you are trying to access a command or exit the screen and that adds some sticky logic to the tool, but it is not something we are opposed to doing if there is a groundswell of support for it. That said, let me start with a few tips and then we will get into App start time. A few tips on panning at the edge of the screen (familiar that Proteus does this and my experience with another tool was very similar). Three ways to do this (sort of):
1) The middle mouse button (or two fingers on a track pad) will pan the screen. This is sort of "clawing your way" thru the workspace but it is how I've grown accustomed to using the tools and it feels second nature after a while with a bit more precision because you control the motion / magnitude and it is multi-directional.
2). Setup a shortcut to "Center" the screen when you want...the image below is a quick way to do this and I have mine setup to use Shift+C in the image and on my computer. This proves helpful in a lot of circumstances.

3) (Final tip) if the middle mouse button causes a lot of fatigue you can use the command line and enter the following sneaky, super-secret command to set a mode that lets you pan whenever you use the Ctrl / Cmd key...
SET Interface.UseCtrlForPanning 1
...You can unset this by setting the value to 0. The SET command is setting some background preferences that are beyond what we expose (typically) thru the UI. This is why I suggest it is "Secret" but there is plenty of documentation for this in the online help if you search for the SET command in the command reference documentation. Use at your own risk perhaps but it wont corrupt the data so that's pretty safe (it just might block some other Ctrl+Click options in the shortcuts if they are using Ctrl).

We try our best not to paint ourselves into corners so some of these options are "hidden away" but there, intentionally and by design. This flexibility gives us the ability to pitch a few options to you without inundating you with features and options unless you need them and we are always willing to help.
NOW...to the start time. You hit this one on the head. There is a lot of stuff we do behind the scenes when the SW starts and we are making progress on improving this. One thing to note is that this is generally a one-time cost when it starts. My only advice until this speeds up is to leave it open. I will have Fusion 360 open sometimes for weeks on end and I just save files but almost never close the SW unless there's an update I want to install. Truth is that most other ECAD packages I've worked on have a "temper" when left open and something starts leaking and it crashes. You see it when they slow down a couple of days into things. Fusion is pretty good this way but if it starts to slow, close and reopen. It takes a bit and we are deliberately working on this outside of my team (but we are working on it). So again, you are correct and we will concede this is taking too long for our own comfort, much less yours. (oh and FTR, one way to motivate developers is to make the SW long to start up...that has the undeniable effect of hitting them 20 times a day when debugging something and it doesn't last long before someone takes that issue on, full-steam!)
Hope these things help and hope you can snicker a bit at my snarkyness. As an EE and someone building the tools I have always had headaches even with SW we built within my team(s). We are not at all unwilling or unable to fix things but we also have that EE-feistiness that comes with the territory I suppose. We know these things can be annoying and even urgent however and so we will do everything we can to help you. I want to get you moving is all. Help you get up to speed and learning the tools. It helps us if people just hit us with questions and we dont end up parsing things within the material but it's crystal clear and we understand the urgency - ie "I'm annoyed," or "I'm blocked" or "I am missing deadlines because of..." That kind of real-world stuff cuts across the team we have which is largely staffed by people VERY familiar with those pressures and we can relate. We promise, we can relate!
Best regards,
matt - Autodesk
Director - Fusion Electronics, Tinkercad