You can certainly create a sobject instance in client and pass as it as array from the component and retrieve it as List<sObject> in the controller.

If you want to pass a specific sObject type you, have to set the sobjectType.

For eg: sobjectType to Account

Here an simple example to do it.

TestApp:

<aura:application controller="AccountController" access="public">
    <aura:attribute name="accounts" type="List" access="private"/>
    <aura:handler name="init" value="{!this}" action="{!c.doInit}"/>

    <aura:iteration items="{!v.accounts}" var="acc">
        <ui:inputText value="{!acc.Name}"/><br/>
    </aura:iteration>

    <ui:button press="{!c.saveAcc}" label="Save"/>
</aura:application>

TestAppController.js

({
    doInit : function(cmp, event, helper) {
        var acc = [];

        for(var i = 0;i < 5;i++){
            //set sobjectType to Account, if account is passed
            acc.push({'sobjectType':'Account','Name':'Test'+i});
        }

        cmp.set("v.accounts",acc);

    },
    saveAcc : function(cmp, event, helper) {

        var action = cmp.get("c.insertAccounts");
        action.setParams({
            "acc":cmp.get("v.accounts")
        });

        actions.setCallback(this,function(resp){

            var state = resp.getState();

            if(state === 'SUCCESS'){
                console.log(resp.getReturnValue());
            }
            else if(state === 'ERROR'){
                var errors = resp.getError();
                for(var i = 0 ;i < errors.length;i++){
                    console.log(errors[i].message);
                }
            }

        });

        $A.enqueueAction(action);

    }
})

Apex Controller:

public with sharing class AccountController {

    //if sobject is specific for eg:Account,then you use List<Account> acc
    @AuraEnabled
    public static String insertAccounts(List<sObject> acc){
        try{
            insert acc;
            System.debug('acc'+acc);
            return 'success';
        }
        catch(DMLException ex){
           AuraHandledException e = new AuraHandledException(ex.getMessage());
           throw e;
        }
        return '';        
    }
}

Trying to pass the datetime (in the input) through the JS to the apex controller - This one is working now

I would suggest provide some more information about what have you done with the first requirement what kind of JS action invocation you did.

Update: (thanks to @sfdcfox for mentioning it Lightning Enabled tag question)

Using Lightning:

If you are looking that thing in Lightning perspective then I'm assuming you used @AuroEnabled Client-server enabled menthod to pass the Date into apex controller, Now use action.setCallback() to invoke another method and pass your parameters from JS directly via action.setParams().

see below reference on more info: https://developer.salesforce.com/docs/atlas.en-us.lightning.meta/lightning/controllers_server_actions_call.htm

see more info on action.setCallback(): Use of setCallBack() in Lightning

Using Visualforce (Conventional Way):

There are various ways to invoke any second method/action on completion of other, it depends on your first action invocation type. If you want to use JS for calling action then use <apex:actionFunction>, it supports rerender attribute which will helps you to rerender the result on the page side.

if you used <apex:actionSupport> or <apex:commandLink> or <apex:commandButton> or <apex:actionFunction> as your first invocation, then you can use onCompletion attribute of these action methods, and in that oncompletion you can call any other <apex:actionFunction> which eventually calls your controller action.

see more on <apex:actionFunction> : https://developer.salesforce.com/docs/atlas.en-us.pages.meta/pages/pages_compref_actionFunction.htm