And if you used before Toodledo, but you faced a restriction in these kind of management, to which software did you migrate?
And did you feel free of limitation now?
I am a former user of Toodledo. I had a PRO subscription to their web version for desktop use and I synced it with Appigo's Todo app on iOS (never liked the Toodledo iOS app, very clunky). When I left Toodledo, I used Appigo's own web desktop version for a while but eventually left that too and went to OmniFocus (Mac desktop and iOS).
Toodledo was never specifically designed for GTD. The owner/developer created it for his own personal use and was able to monetize it by offering subscriptions. Ongoing development was done primarily on the basis of what he found "interesting" rather than on what users were asking for. I found that frustrating.
The two problems you raise are what most GTD followers struggle with, i.e. Projects and Areas of Focus. Toodledo just isn't designed to cater for this well at all.
The way I set up Toodledo was to use folders as my main GTD buckets, e.g. Today, Waiting-for, Someday/Any day, etc. As there was no specific inbox, I had to create a view showing items assigned to 'No folder' as my inbox.
Given that I was using folders in this way, projects had to be parent tasks with sub-tasks as the various steps in each project. This caused a problem in that when project sub-tasks are viewed outside of their hierarchy (i.e. in a specific folder), you can't see the parent task so you can't see its relationship to the parent or other sub-tasks (as they may be in a different folder/bucket) so it made project control difficult.
I also tried using Tags as my GTD buckets and switched Folders to be projects. From memory this introduced other problems, e.g. you have to be careful using tags because they are free-form entry (i.e. not a validated/defined list) so you can inadvertently create two that are almost identical.
It seemed that no matter which way I tried using Toodledo for GTD, there was always a significant compromise. And because it was so flexible, I was always tempted to keep tweaking the system to see if I could make it work better, which of course was a waste of time.
In the end I realised that it was never going to get better - the developer introduced what I considered zany new features from time-to-time that absolutely no-one in the user forums had asked for yet he ignored countless repeated requests for basic improvements. After pestering him about this on more than several occasions following an update, his eventual reason (as mentioned above) was that he developed features based on what he found was "interesting" (e.g. trying out a new coding method, or a new technology). It just wasn't a normal commercial product and didn't ever seem that it would be.
OmniFocus is the polar opposite - carefully developed with GTD in mind, every feature highly considered for its worth and value to the user community, very powerful yet a simple intuitive interface with some flexibility in viewing the data, and well-supported by professionals who care about what they do. It's refreshing.