It is correct, that the MCPD 3.5 regarding Windows Forms and ASP.Net is quicker to archieve.
But it is much less worth. The new 4.0 MCPDs can be more compared to the MCPD Enterprise 3.5.
And the exams required on 4.0 are not 4 - you need 5 more exams:
4 MCTS and one PRO exam. (Please see
http://www.microsoft.com/learning/en/us/certification/cert-vstudio.aspx#tab2 for details!)
So if you just want to get any MCPD, you could simply get a "cheap" MCPD. Or if you do not want to do that many exams, you could go this way:
Get MCPD in 3.5 (2 Exams) + 1 Upgrade exam so in total 3 exams only. But this will not be an easier way, because in the upgrade exam, you need to proove, that you know all these technologies. I think it is easier to take the single exams instead of an upgrade
exam.
I hope I was able to help you.
With kind regards,
Konrad