Raul,
What you are looking for is CASE tool (Computer Adided Software Engineering tool). There are (at my last count) around 666 such tools (I hope the number is a co-incidence!). There are 2 basic types of tool - those that are platform dependent and will end up generating code and database schemas on that platform, and those that are not. From the outline of your requirements you gave I would suggest that you should look at non-platform dependent ones. CASEWise (http://www.casewise.com/Products) and ProVison (http://www.metastorm.com/products/mpea.asp) are good examples - I have used both extensively and they are intuitive (I never had a training course on them!) and can be customised: you can set up your own objects to use, track and control in a networked shared repository - you can even set up your own method to an extent.
Two words of warning though:
1. 75% of CASE tools purchased fall in to disuse - this is a shame as - if nothing else! - they are expensive. Check out a talk I gave to the ProVison user conference at http://www.businessanalystsolutions.com/The%20Business%20Analyst%20The%20Business%20Model%20and%20the%20Strategy.pdf for possible reasons why. The bottom line is put someone who can't drive in a Ferrari and what you get is a broken car (at best) or a big car crash fast! In other words, you need to know how to do analysis before you start using a CASE tool or it will allow you to make a big mess fast!
2. They won't do stuff outside of their remit unless you bend them and I have never seen that work. The reason I mention this is that you list MS Project as one of the applications you want to replace. MS Project models project plans, not the products of project analysis. Some CASE tools will be able to embed MS Project Plans but they do not do project planning and I would recommend that you don't try to make them do it either.
...and finally - so you might be sourcing a piece of software (CASE tool), so why not analyse your SMART objectives, dependant requirements, and resulting process and data rules first for that software and then go through a procurement process of request for information and invitation to tender. In other words, we analysts can apply analysis of requirements to ourselves (and not just for sourcing CASE tools by the way - how about doing that for the BA function we are a part of?!).
I hope some of the above is useful.
Guy