Most outsiders don't care, at all, what effect a leader had inside a sect, but how their work affected the outside.
https://www.nytimes.com/2018/01/03/obituaries/thomas-monson-...
I scanned through http://newsdiffs.org/article-history/https%3A/www.nytimes.co... as well. Nothing stood out as a fundamental change that would explain why the blogger's unbiased perception could be different from others'.
The LDS Church spends less than .5% of its income on charitable donations ($40 million/year), and currently owns 2% of Florida and a $100 billion dollar investment fund.
The Church of Jesus Christ of Latter-day Saints does not release their charitable financials to the public (because they believe in the Biblical tenet not to brag about one's charitable work for the praise of the world). The only solid number released was related to their LDS Charities organization, which has donated $2.2 billion in 197 countries since 1985. This branch does not represent the totality of their charitable work. It is just one organization. For example, this number does NOT include the charity their bishops dole out on a weekly basis, does NOT include donations through their Perpetual Education Fund, and does NOT include the time/money their individual members give.
They recently offered more information about their charitable work throughout the world and claimed their charitable donations equal "billions more" than the $2.2 billion mentioned above (https://newsroom.churchofjesuschrist.org/article/church-of-j...).
Because there are no solid or accurate numbers publicly available, we really don't have any idea what percentage of their income goes out to charitable donations, so these kinds of statements are simply not valid. Does it really matter though? In my opinion, another person's charity isn't any of my business. Who am I to judge another person's gifts?
Yes, the church invests excess funds, and it does so to secure it's ability to continue its current outlay long term. There were times in the church's history where it was in need of money, and it does not want to ever go through that again.
Other charitable organizations also invest excess funds for similar reasons. The church additionally believes in a breakdown of society before Christ comes at the end of the world, so doesn't it make sense for that same organization to diversify their assets?
Personality, I wish the church was more open with how donations are used, and honestly I think churches should be required to be transparent in how funds are used, just like other classes of tax exempt organizations. However, that doesn't mean that slamming an organization over mere speculation makes sense. There may be a story there, there may not, but we won't know without more information.