Is the ranking system still good today?

LTJG (Join to see) -- interesting question. You talked about saluting and a little about learning and leading. Saluting isn't really an issue. It's an honor to give and return salutes--end of discussion. Each group of ranks has specific purpose within the service. Your lack of experience as an officer and school status may make this more difficult to see, but it will be more apparent aboard ship/boat. The military rank structure is mirrored in private and public organizations that choose to manage using a hierarchical system, so the military isn't alone in its approach to management. Let's look at it from the bottom up.
-E-1 through E-3 or E-4 (depending on service): hands on execution of mission, front line combat force (except aviation)
-E-4 or E-5 (depending on service) through E-6: first-line supervisors lead the execution of the mission at the tactical level
E-7 through E-9: Senior supervisors and superintendents lead the first-line supervisors; do some planning and budgeting activities; set and sustain standards; participate in policy making. Work at operational level in general.
Warrant Officers: highly specialized technical experts. May have leadership positions and in some cases command authority. Responsibilities and authorities differ by Service and specialty. Front line troops in aviation in some services.
O-1 through O-3: entry level managers (except aviation). Greater scope of responsibility and authority than NCOs or WOs. Intended to learn both their technical specialty and leadership. Manage resources and lead people at tactical level. Must understand orders from higher authority and develop plans and secure resources to execute the mission. Transmit intent and direction to subordinate officers or NCOs. In aviation, front-line mission executors. May command front-line organizations.
O-4 through O-5 or O-6 (depending on job and Service): mid level managers. Participate in planning and policy making. Manage groups of groups of people. Expanded scope of responsibility and authority to translate general orders, commander's intent, and policy into actionable direction to lower level organizations for execution. In aviation, first-line supervisors and organization commanders. Work at the operational and strategic level.
O-6 or O-7 through O-10. Senior managers or Commanders. Equivalent of corporate officers (vice presidents, presidents, CEO, CFO, CIO, etc.) Manage policy development, set mission and vision for organizations, lead large organization. Direct work of staffs and subordinate commanders. Lead at operational and strategic levels. Command at strategic level. At highest levels advise the SECDEF, Service Secretaries, and POTUS.

Throughout there is responsibility to teach and mentor subordinates while expanding and developing one's own technical knowledge and skills and leadership abilities. Keeping the lines of communication open from top to bottom and bottom to top is a good leadership technique and essential to effective operations. Junior officers should remain open to learning from both their subordinates and superiors, but remember their place in the organization maintaining professional relationships and avoiding fraternization.

Late add on: There are exceptions. Services may use early promotion as an incentive for joining, reenlistment, or retention of some service members in particular specialities. Examples include special operations who appear to advance rapidly to E-5, Navy Chief Petty Officers who become warrant officers immediately moving up to CWO-2; doctors and lawyers start out as O-3s in most cases and sometimes above that. Below-the-zone promotions can advance service members rapidly causing them to attain higher ranks withour the requisite experience.

I have never had issues with the system, IMHO it should be left alone.

You might be confusing rank (a control structure) with learning (gaining skill and experience). They are not intended to be congruent. Juniors typically don't have much to offer in the experience department, hence get it elsewhere. JOs/Junior NCOs are a team with shared responsibility. Senior Officers/NCOs have a similar set up. We look to effective experience, wherever it lies, to help us understand and perform our job better. And that experience in a junior in rank is to be respected. Remember, learning something doesn't mean you take over doing it. That's the problem in the "I went to college and know it all" types. The NCO reaction will be to hold back and let the JO fall on their own sword. There's things a JO can do that the junior NCO cannot effectively. Best outcome is for both to stay in their effective swimlanes and work together as a team.