Ranking these hands based on their EV seems perfectly reasonable to me.
Personally, to list from strongest to weakest, I would just sort by Win% (descending) and then Loss% (ascending), so your hands above would be ranked the same way you arrived at with your "0.5 points for a Tie" approach:
/----------------------------\
| Rank | Win% | Loss% | Tie% |
|------+------+-------+------|
| 1 | 45 | 40 | 5 |
| 2 | 40 | 40 | 10 |
| 3 | 40 | 45 | 5 |
\----------------------------/
Note that in this case, the Tie% is actually irrelevant as if two hands have the same Win% and Loss%, they must by definition have the same Tie%.
This just represents the EV of the hands though, you could equally arrive at the same result by scoring each hand as:
1(Chance of Winning) + 0.5(Chance of Tie)
so for example your 45% Win, 40% Loss, 5% Tie hand has 47.5% equity/EV in the pot:
1(0.45) + 0.5(0.05) = 0.45 + 0.025 = 0.475 (47.5%)
Which gives the same rankings a different way (and is the approach you proposed):
/-------------------------------------\
| Rank | Win% | Loss% | Tie% | Score% |
|------+------+-------+------+--------|
| 1 | 45 | 40 | 5 | 47.5 |
| 2 | 40 | 40 | 10 | 45.0 |
| 3 | 40 | 45 | 5 | 42.5 |
\-------------------------------------/
If you wanted to somehow skew the results so that chips lost have a greater negative impact than chips won have a positive impact, then this would take some more consideration and surely would need to depend upon specific situations, tournament payouts and such to be meaningful rather than arbitrary?