There's such a quantity of Steem Power and liquid STEEM detained by the "founders" that they could easily crash the value or organize pumps and dumps (and seeing large transfers like that, it may be to cover expanses, it could also be for manipulating prices, and with no information, we can only speculate).
Given that the steem graphene-like blockchain is a distributed public ledger, not sure how much more transparency is actually needed. Steemit Inc would in theory; not do a massive sell-off as this is counter-productive to the growth of steemit.
For the distributed ledger, OK all transactions can be seen, you won't be able to do much more on the Steem blockchain. But you can't see what's happening on the exchanges, so it's Steemit Inc.'s role to clarify and explain their actions.
For the manipulations, sure, Steemit Inc has no interest to dump the price.
But the real questions are
Who is really behind these accounts ? Who has the owner keys ? For me, it seems like Steemit Inc., the @steemit accounts, the founders' accounts, all that seems a bit confused, and with no clear links of who owns what and no transparency of propriety, it's hard to see where the real interests lie.
Steemit Inc. has interest in the long term growth of Steem but who tells me they're the ones with the real power and with the highest stake in this ?