Money and credit will always seek the lowest cost environment. The micro dynamics of markets where there are different players seeking to reach various objectives is all the more critical when thinking about crises, liquidity, regulation, and pricing. The microstructure of markets matters and the behavior of players toward changes in the "rules of the game" is important. In an older school of thought, this would be called market structure or industrial organization. In the current environment, we can relate this market networks.
If you believe that markets are efficient, then the behavior of players in a network may not matter. If you believe information comes from disparate sources both exogenous (from economic policy announcements and data releases) and endogenous (based on the players in the market, hedgers or speculators), then the network and connectedness of player matter. More importantly, if the costs for trading change for agents in the network, the connectedness of players will change. The efficiency of the market is based on the interaction of dealers, traders, and hedgers.
The network approach will suggest that regulations that change the cost of trading or place restrictions on traders will impact the efficiency of markets. If the cost of trading is higher, arbitrage may be more expensive and there will be more market frictions. Price relationships will change with the relative expenses of trading.
A network view of market behavior will focus on structural changes that will affect the flows of information and capital through the network. Systemic risks will change with the blending of the network. The systematic risks of yesterday will be different today when you change the costs to players in the network. Follow the transaction, regulatory, and capital costs to determine the changes of risks within the network. Then follow the money through the network. The simple answer is that the systematic risks today will be different than from 2008 because the network of trading has changed.