Even the most optimistic investor may get second thoughts whether this is such a great idea.
Nokia mentions more than five dozen possible risks, whereas each single one could jeopardize Nokia's future business. Many of those risks refer to circumstances Nokia cannot influence, such as the fact that WP7 is an unproven platform and that the partnership may hit roadblocks that could prevent Nokia from competing in a timely manner. Of course, there are the upsides as well, which may not really be upsides for Microsoft.
Nokia expects that the partnership will give the company access to resources to help the company design devices that will be different than competing Windows Phone 7 phones. Nokia also notes that it will get significant advertising and marketing support from Microsoft. There were no further details, but Microsoft's WP7 partners could see this partnership as a threat to their business and could possibly distance themselves from Microsoft.
Nokia is a strong partner for Microsoft, but WP7 needs all the support it can get. Losing partners is the last thing Microsoft needs right now.