Good question. The point of the nodes is to allow for axonal depolarization to hop over short distances rather than having to move along the entire length of the axon. This speeds up transmission of an electrical impulse along an axon.

Now the Nodes of Ranvier already have the highest concentration of sodium channels anywhere in a neuron. In particular the type of channel is the NAV1.6, which stands for Sodium (Na) and Voltage (V) family 1.6 aka Voltage gated Sodium channel. Importantly for your question, this is also a channel which has an inactivation gate.

Voltage activation means the channel is activated by a strong enough differential in charge across the membrane. This charge is what can "hop" between the Nodes. Inactivation happens after a sodium channel is opened. It has a plug, just like a sink drain. So, when the channel opens and lets in sodium the plug will quickly fill up the channel and stop ion flow. This is useful because it allows for an electrical signal to trigger the sodium channels in a node, allow those channels to respond by opening and allowing sodium ions to cross the membrane thus regenerating the depolarization signal, then quickly and completely turn themselves off.

The critical reason this feature is essential is to prevent retrograde flow of the electrical signal. Each Node is just as far from the next node as it is from the one before it, so the electrical signal can reach the nodes on either side of it, But we only want the next one along the axon to be able to respond to it. By inactivating the sodium channels, a node becomes very temporarily unable to respond, and it turns out that period is just long enough for the signal to traverse down the axon.

Now, there are only so many channels you can fit in a certain membrane space and still have it function as a barrier, so it's possible the Nodes of Ranvier have already achieved that. You might also run the risk of changing the speed or degree to which the sodium current activates which could change how quickly the sodium channels inactivate. This could cause leak of signal backwards, or cause inactivation so strong, the sodium channels are still turned off when the next signal comes along, and the axon accidentally misses messages.